Another big thing is trust. With any of these digital markets I'm not truly buying games, I'm purchasing a revocable license. That requires a certain amount of trust that the platform isn't going to screw me over.

Steam isn't perfect: they initially had to be forced to offer refunds, and their item economy enables barely disguised gambling. But by and large they have behaved very predictably and consumer-friendly. Sometimes by outright consumer-friendly policies like generous refunds or labeling games with AI assets. But usually by just not doing anything greedy. Or as the meme goes: "Gabe does nothing. wins."