Are workout clothes just for aesthetics?

I don't mean to be trying to put people down for buying these clothes or anything. Even if they were for looks only (which idk yet) its not my business what other people spend money on and if buying a nice shirt makes them more likely to workout and maintain a healthy lifestyle then it is definitely a good investment. All that being said, are they for looks? I've exercised on and off for years (currently on a 5 month streak) and i was a distance swimmer for several years like 10 years ago. So im not a stranger to the gym but I've also never spent more than an hour in the gym at a time.

For Christmas i got some workout clothes. Which are nice. I wore them a few times already but to me it's the same as what i had been wearing. T shirts and sweats just a different material. Or does the benefit of these clothes only kick in at a certain level of activity/sweat? Because i sweat at the gym but im not soaking through shirts or anything. Is there a benefit to sleeveless? I see a lot of sleeveless stuff. Does it help you see your form or something? Or is it just less sweaty/cooler without sleeves?