Onsieses?

I’m not trying to come off as rude.. I just am wondering if anyone else child or children still own onsies and how often they wear them?

My sons girlfriend lives with us and has since Christmas time, she have five onsies, and she wears them all the time, she get upset if she doesn’t have at least one, throw a low temper tantrum until we can find one for her? She’s 16 as well she has some days were she will put on “normal clothes” but a few hours later her onsies right back on ,I’m just curious if anyone’s had this issue? I’ve looked stuff up, I’ve even talked to her mom😊