All stablecoins (at least popular ones) has the same underlying problem -- it's regulated and controlling entity can freeze any funds because it wants so

Yeah, but so can PayPal and Visa and Mastercard. The issue here is that payments is essentially a duopoly. Itch doesn't have any alternatives because they're locked into traditional payment rails. Stablecoins at least let someone else decide "Hey, you know what, I'm going to create a coin that can be used as payment for porn games." And executing on that is fairly straightforward.