>>88616702Because why the hell not?
Actually, a few heroes and villains have explained why. For the heroes it's because that's their symbol. Superman wouldn't be quite as striking if he wore a t-shirt and jeans
though casual Supes is probably my favourite costumeAs for villains, the one's that aren't bugfuck crazy/need their costumes to control their powers, it kind of legitimizes them. Heatwave, a Flash villain, basically summed it up as "if I run around burning houses down, I'm an arsonist. If I do it while wearing a costume, I'm a supervillain".
