Some people do like the occasional validation of someone else finding you sexy. And as long as the partner is okay with that and it’s doesn’t get too much, what’s wrong with that? Sometimes it’s just nice for the confidence to know, that you look attractive or sexy. And who are you to decide that no one needs that to feel confident? And who can you differentiate if someone’s dresses a certain way to look attractive or to look sexy?
Also if you feel sexy that can benefit your partner as well, when you feel sexy you’re more likely to act in a sexual way and confidence regarding your body can help be more open sexually etc. If you don’t feel sexy, don’t like your body, you’re more likely to be in your head during sex and overthink stuff.
Something that seems hard to understand for some people is that what matters is what the two people in the relationship think and that there’s no universal rule.