Why does he wear clothes?

Finished the book a few days ago. Sometimes Rocky's admonishments to "sleep, human stupid when no sleep" felt like he was talking to the reader as well, but I really wanted to see what happened next.

Anyway, it's mentioned that Rocky wears a little shirt thing, and I'm wondering what the purpose of that is.

Their hearing is super accurate and their carapace is pretty thick, so they can probably see right through the "clothing" and not really feel it on their "skin". They regulate their temperature through their radiator organ, so I don't think it's to keep them warm, as they usually are trying to lose heat, and their ship is temperature controlled. They excrete and eat through cracking the bottom of their body open and then resealing it, so that as well as the radiator are left uncovered. It's never described as them having a sense of nudity, so is it just ornamental? They have their celebration outfits, so maybe they also have their daily outfits they wear to mark the occasion as normal? Maybe it has a nice muffling quality, or maybe it's something special only Rocky wore/wears since he's the engineer and gets down and dirty with stuff and it helps protect him?

Why do you guys think he wears it?