I might be in the minority since I could not care ANY less about costumes/ skins, but I don’t mind if a game wants to promote things that do not influence gameplay.
I personally take issue when games put content or characters or things that directly impact performance or progression (like weapons or armor) begins paywalls, or if producers uses lootboxes (essentially promoting gambling). But if there is an actual market for cosmetics and fans want to buy them, I say more power to them.