Sure, but at least Dota and CsGo don't hide any game-relevant content behind a paywall (I've played TF2 a bit, and having different weapons unlockable really isn't fair).
Also, just a cool thing, you can generally sell the cosmetics from TF2 and CSGO (never played DotA, so don't know), so If you don't care about it, sell it on the marketplace, some enthusiast will buy it, and you get 3 bucks to spend on the next sale.