And I think there's a big difference between the two.
The only real difference is mindset.
The actual characters at the table may well be identical, mechanically - they'll just be played very differently!
Someone who plays something they don't even like, simply because it's powerful and that's all that matters to them, not even having actual fun, is, frankly, at best a rather immature/childish individual, because TTRPGs aren't about winning/losing (c.f. the thread discussing this). That's kind of the true munchkin spirit - so into "winning", that they'll do anything, even playing a PC they hate!
When I was a teenager I actually saw that in action - one of the players, who was going through some stuff at that point in his life (not that we were wise enough to realize it), had become a total munchkin, and ended up playing some kind of ludicrous character who he just didn't even like at all, I think in SLA Industries.
What was really sad was his character wasn't even that good - he'd messed up because he didn't understand the mechanics as well as he thought, and he ended up playing a character who he both hated because he didn't want to be a skinned-horse-looking dude (I remember this so it has to be SLA Industries I think unless there were similar races in other gun-oriented games), but who was also not as good at killing people as the other PCs were (and wasn't good at anything else, either).
That's part of what this discussion is missing, because most people are operating in 5E D&D in 2025 mindset and thinking "Oh well you can just look up OP builds online!", but that's not true for 99% of RPGs out there, and it's not true historically either. People assume "breaking the game" is successful, but the very people most prone to try and make "broken" builds are often not successful, in my experience (or are one DM ruling - not even a "house rule", just a decision on an unclear point - away from being un-broken), and I think that factors in and helps also to identify people who are going to be an issue.
The real problem, when we zoom out, isn't "optimization", it's just players with bad attitudes. The relevant subset of that problem here is "players who think TTRPGs are about winning and losing". The subset that subset that causes most of this grief and annoyance is what I'd call "munchkins" (other people may have other terms, it's petty nonsense to pretend I'm demanding that one, but we should avoid vagueness like "optimizer" for this) - i.e. players who:
A) Think you can "win" TTRPGs
And
B) Think they should do absolutely everything they can in order to do so!
But they're not the only subset of that "players who think TTRPGs are about winning and losing" group - hell one of the others is "people who continually obsess about the power of other PCs and fulminate about it", which I've seen from actively anti-optimization people (as well as pro-optimization ones). Bad attitudes are the problem and they're definitely not limited to "optimizers".
TLDR ("you" is directed at munchkins here, not people in the thread):