Im not saying buying a skin is skill expression. When a player is playing they are preforming in front of an audience, everything is part of how they express themselves. From how they move to how they shoot to the skins on their gun its all player expression. Not everything has to be an achievement to be proud of some stuff you just like because it makes YOUR character look the way you like. I dont know how to convey this idea properly.

If its a f2p game where cosmetics cost nothing people still choose cosmetics over the default character. This is because your ingame character kind of represents you when you play online.

For your second part about spending money on games I feel like you are being intentionally obtuse. I dont only care about money going to devs. The game isnt made by just devs. I want it to go to the entire company that produced the game I'm playing. If investors get paid thats good I'm glad they are getting a return on investing in the creation of a game I like. If the game made no money there wouldnt be people getting hired to work on it. A f2p game is exactly like a tip jar no one has to buy anything and if no one buys anything the game shutsdown.