A lot of my songs this year will likely be silly little punk/thrash songs and there's no reason why short songs like that can't be seen as legit (cf. Short Music For Short People compilation, Syntax short song comp, You Suffer, etc). It feels absurd saying this as someone who is notorious for creating extended length tracks lol.
I don't think there's any official policing on it, but I just thought I'd create this thread so people who make very short tracks can chime in and feel just as legitimate as those who write longer songs