#4 You get TF2 items and hats in ‘Genuine’ quality.
Don’t care for Hitman: Absolution? Well, that’s too bad, because if you don’t get it, you’re going to miss out on that fancy little Hitman-themed penguin for Team Fortress 2. And you do play Team Fortress 2 a heckuva lot, don’t you? Couldn’t you just buy the items from the MannCo Store? Of course you could, but they wouldn’t come in green ‘genuine’ quality text.
Why should that even matter? It shouldn’t, but Valve’s clever study of human psychology would indicate that we get some dopamine rush out of bling, and bling in TF2 just so happens to come in the form of green text.