maybe because it’s a lot of shine, chrome, nice smells, staff standing around looking luxurious, whereas if there are racks of clothes, it looks ordinary and not welcoming. just a guess.
It’s pure marketing, once you get into the racks, you are not going to be interested in having someone come over and bother you.
Higher ticket items like cosmetics are something that sell more when a dedicated salesperson is on hand. Those walk by makeup demonstrations and scent displays sell a lot of product and they don’t want you to have your hands full because you will be less likely to stop.
It is because they inspire impulse buys. You don’t have to try them on. You are walking by and see something you can pick up quickly for yourself or a gift. It’s why jewelry is the same place often.