Capes: Capes originated as a low tech raincoat. As actual coats were invented, capes hung on for a while with the upper crust because they serve the purpose of keeping the splashed mud and dung off your fancy clothing without entirely concealing it. Certain entertainers retained it as well because it lent itself to dramatic flourishes. Elvis wore a cape. James Brown wore a cape. Bullfighters wear capes. Those are the associations with cape wearers. They're attention seekers and/or aristocrats. The capes signal status. Zorro and Batman wear cloaks because because they are eccentric rich guys. Robin is a circus aerialist. Superman is originally dressed like some kind of circus performer who is half strongman, half acrobat. Later on his look becomes more aristocratic as befits his status as the pre-eminent hero of his world. Thor is prince of Asgard. Doctor Strange is Sorcerer Supreme In my list above I have two cape wearers, Vigilant who is the son of the first four-colour super in his world and Lady Nemesis who is the daughter of that super's arch enemy. They're superhero aristocracy, complete with capes.
There are exceptions of course. Cloak wears a cloak just because he's the Cloak part of the team of Cloak and Dagger. Spawn doesn't so much wear a cape as a cape wears him. It's also worth bearing in mind that there's a distinction between ornamental and functional capes. Spawn's cape is prehensile and stretches. Doctor Strange's cape lets him fly without needing to cast a spell. Devil-Slayer's cape is a portal to hammerspace.