Look “good”? Come on. If not having the Pickle Rick decal for your car makes you play worse it has nothing to do with looking “good”. Perhaps look “like I own this exclusive cosmetic”, which applies to offline as well, don’t you think?
The real problem is that loot boxes are gambling, and are addictive, period. It triggers something in otherwise rational people, especially children, that makes it feel good to spend money on mostly non-gameplay-altering cosmetics.
At some level it probably does. Even in Rocket League, which is more cosmetic than most, if your teammates are passing to you more than they would have with the default skin, then you'll do better.
As a medic in team fortress 2, I usually pocket and ubercharge the players with cosmetics. It's an important team resource, and the odds of someone with a "default" skin making good use of it are fairly low. Much like plumage for a bird it's a reliable signal of "virility" - if you're invested enough in the game to own a $200 hat and a coordinated outfit then you've probably played it long enough for me to trust you sight-unseen.
If you're a pro player with the default skin, you're gonna have a bad fucking time, because you're last priority for heals, you're not getting an ubercharge, etc. That is gameplay-affecting even if the cosmetic itself is not.
This is the first really good example I've seen of cosmetics having a gameplay effect. I hate that it's true, but I really appreciate you mentioning it -- signalling of skill is super valuable, and if cosmetics are a reliable enough signal, that's interesting.
If you make all skins and cosmetics available to everyone then you're back to square 1 and people will use some other heuristic to decide who they should pass to. I think this is actually an argument for paid cosmetics, it would improve gameplay for the people who spend the most time playing the game by allowing them to identify other people who also dedicate a lot of time and money to the game.
Oh I totally agree that the system right now is majorly screwed up. Loot boxes are absolutely gambling (why else would the odds be legally required to be disclosed in some jurisdictions?)
And of course it's a vanity component (at least for me, though other posters have raised other factors). Everyone's different with different preferences and as long as there's not a problematic spending aspect I think it's fine...but this links back to the gambling issue. Personally I only buy cosmetics in a few games I play a lot and that don't use loot box mechanics.
The real problem is that loot boxes are gambling, and are addictive, period. It triggers something in otherwise rational people, especially children, that makes it feel good to spend money on mostly non-gameplay-altering cosmetics.