NBN has an unfortunate history of impotent ICE, with criticisms ranging from "porous" to "useless" to "weak" to just plain "terrible." Capacitor isn't helping those stereotypes.
But wait! I hear you say, 4 for 5 strength is amazing, with just a little bit of support, this could be one of the most cost-efficient pieces of ICE in the game! Eli 1.0 levels of efficiency, without any of the porous drawbacks associated with Bioroid ICE.
OK... let's be objective and consider all the possibilities
How good is this piece of ICE without support?
How good is this ICE when the runner has a single tag
How good is this ICE when the runner is buried in tags
How good is this ICE when paired with guaranteed tags (such as having a Funhouse installed on top of it)
Scenario 1:
Pretty terrible. 4 for a 3 strength 1 sub barrier is atrocious, Cleaver, the gold standard Fracter eats it for a credit and you'll notice that no other 3 strength barrier sees consistent play for this exact reason. I've almost never seen Klevetnik and Maskirovka and I've only really seen Hafrún as part of Stavka Ob Superheavy Logistics: Extract. Export. Excel. combos. All good Barriers in the format fall into 2 categories: cheap, utility gear checks like Tatu-Bola, Ablative Barrier or Ping and large value ICE like Bran, Logjam, Pharos and arguably Boto. Capacitor without tags has the misfortune of falling right in the middle, where you end up paying a rez cost that is twice as much as an Ablative Barrier for the exact same taxing power, without any chance of recursion to sweeten the deal. I feel confident saying that as long as Cleaver remains the go-to Fracter you should never play Capacitor without tag support.
Scenario 2:
The runner has a single tag, you're probably playing some sort of tag punishment so the runner is almost certainly not ending their turn tagged, so we'll assume that for the sake of argument, they somehow managed to take a tag on their turn, maybe they've run a trap and then run the Capacitor without removing the tag, perhaps they're playing Seb and took a tag for Manuel, perhaps they used Eru. Whatever, it's not important, still arguably a lacklustre piece of ICE, the dominance of K2CP Turbine in the current meta ironically makes the difference between a 3-strength Barrier and a 5-strength Barrier somewhat mute, and the difference between having 2 live subs and 1 live sub equally as irrelevant when it comes to Cleaver. Perhaps if you're expecting more Shaper playing Gauss/Pressure Spike or Criminals playing Curupira then maybe you tax them an extra 2 credits, maybe an extra 3 credits if they're willing to spend a credit to deny you a credit but considering how niche a situation this is and how meagre the increase in efficiency, I'm still not about to include this ICE just because my deck happens to give a few incidental tags.
Scenario 3:
The runner is swamped in tags, we're talking Behold! into Oppo Research or AMAZE Amusements + Oracle Thinktank into Oppo Research, pick your poison but the fact of the matter is that clearing tags is no longer an option and the runner now has to go "tag me." This does 2 things, first off, the ICE is always 5 strength from now on, rather than needing a niche scenario, and the first sub is giving you 5-10 credits now so the runner really feels the need to break. It's still not very good, everything I said about Cleaver and Turbine is still true and you're still only taxing Shapers and Crims a few extra credits (unlike Starlit Knight which scales continuously with the number of tags the runner has). In total, you tax Shapers and Crims 6 credits with Pressure Spike or Gauss or Curupira (assuming they haven't hit threat, aren't flickering Gauss or aren't bypassing it). These numbers sound good on paper but when more than a third of the meta is on some form of Anarch, when runner econ is so high that even 10-strength Barriers aren't enough to consistently keep runners out and when you remember that the Runner is going tag me so you probably have much better things to do like Mindscaping + End of the Line or Shipment from Vladisibirsk or scoring out a Freedom of Information for free then this ICE really just isn't making much sense.
Scenario 4:
Paired with guaranteed tags, perhaps the most interesting and least conditional option is simply pairing this kind of ICE with guaranteed tags effects, the most obvious example of which is just to install this, then install a Funhouse on top of it, somewhat reminiscent of installing a Data Raven on top of a Data Ward. This way, you guarantee it's always 5 strength, regardless of whether the runner hit a trap the click before or is going full tag me. The only way to beat this is paid-ability window tag-removal like No Free Lunch or Flip Switch and this is probably a poor use of such powerful cards so let's a assume everything works out. This whole situation is still absolutely rubbish for you, you're now paying at least 10 credits (4 for the Capacitor, 5 for Funhouse and 1 for the added install cost) to get yourself a 5 Strength Barrier and a porous code-gate, Yikes! the Runners are just quaking in their boots I'm sure.
As you can see despite the alluring promising of 4 for a 5-strength Barrier the truth is far less glamorous and far more disappointing, this ICE just rarely makes sense, even if you're playing a tag-centric deck your ICE is probably more interested in giving tags to set up other, aforementioned pieces of tag-punishment then getting a slightly more taxing barrier.
This is really a shame because NBN has occasionally had pieces of ICE that made sense in that respect, the perfect example being Data Ward of course, even accounting for the combined install costs of Data Ward + Data Raven (only 11 credits actually) the payoff is so much better, 1 guaranteed tag, + 2 more possible tags unless the runner pays 3 and beats the trace, plus an 8 strength 4 sub barrier, all 4 subs needing to be broken for access so something like Boomerang, Botulus or Slap Vandal will still struggle with it. Capacitor is like Data Ward's little brother, Data Ward's sad, pathetic little brother no less, something that just doesn't live up to it in any respect. Which is a real shame, because the idea of making NBN ICE care about tags and be conditionally really good when supported by something like Funhouse is a cool idea, unfortunately, the simple reality is that Capacitor just isn't enough of a payoff.
This might sound hilarious and maybe I'm just being naive but I do really hope that NBN gets some genuinely good ICE next set.
Thematically a Capacitor refers to a kind of device within electrical circuits designed to temporarily store electrical energy and can be used in power transmission to smooth and stabilize the flow of electricity. How this relates to this card is eluding me as it neither gains nor stores charges or power counters or advancements and it's not like it temporarily removes tags and then releases them like some kind of modern Data Raven or something. In regards to the quote, presumably, Seb is struggling with this kind of ICE because he's exactly the kind of runner who would otherwise normally like to be running tagged but honestly if Seb is playing Cleaver + K2CP Turbine or Arruaceiras Crew or Tsakhia "Bankhar" Gantulga or Botulus or any of the other tools Anarchs have at their disposable, it's really not all that much of a struggle.
TLDR: Yet another mediocre piece of NBN ICE that sees no play, absolutely gets shredded by Cleaver and fails to fill the big shoes left by Data Ward.