CS is wild. I used to play and have like 40+ cases from free post-match drops. Because those cases are no longer supplied, the prices have been creeping up and to the right for years now; from $0.40 to $20+. I don't even know why people still buy these, but I will basically never have to pay for a Steam game again.
I had to check but I barely played CS:GO. I have a 5 year veteran coin, untradeable, that's it lol. I also have a $0.03 gun for Payday 2, lol.
Nearly 300 "trading cards" but they're all valued between $0.03 and $0.10 at best. Weirdly enough, even the randomest games still get some trading volume. I seriously doubt people are buying cards from random games to complete collections in those volumes, and fully expect it to be bot driven and / or some kind of scam. But I assume Valve gets a percentage for every transaction so they don't really care.
I haven't played in years but the core game doesn't seem to have changed much. They tweaked lots: textures, hit-boxes, spray patterns, rankings, game modes, grenade types, guns, etc., but if you play a ranked match it will still be a 5 vs 5 bomb defusal.
The (sellable) lootboxes give you weapon skins. This is cosmetic, but the temptation to express yourself or flex with pretty guns is tempting.