I am not a cosplayer by any means so take what I say here with a grain of salt, but generally I find cosplays without wigs a little "off" looking. Sort of like cosplays that just use normal street clothing.
IMO, for a cosplay to look good it's got to look sort of... fake. I know that sounds strange, but there's a slightly "otherworldly" quality of a good cosplay - even if you don't recognize the character, they still look like they just stepped out of an anime or video game. There's really no way to accomplish this look with natural hair unless you use gobs and gobs of product to almost lacquer it into place.
This is not to say I've *never* seen a good cosplay pulled off with natural hair, but generally I find they look more finished with a wig.
IMO, for a cosplay to look good it's got to look sort of... fake. I know that sounds strange, but there's a slightly "otherworldly" quality of a good cosplay - even if you don't recognize the character, they still look like they just stepped out of an anime or video game. There's really no way to accomplish this look with natural hair unless you use gobs and gobs of product to almost lacquer it into place.
This is not to say I've *never* seen a good cosplay pulled off with natural hair, but generally I find they look more finished with a wig.