*Sigh* Why does nobody ever mention Gamestop Downloads? It's one of the better DD platforms, mainly because it's Impulse with a new skin, lower prices, and a lot more titles, because Gamestop is better at negotiating with the publishers than Stardock was.
Heck, it's not even impossible to sell digitally distributed games in a brick and mortar store. If you can find a gamestop with a half decent PC selection (not always easy), they usually have a shelf with display cases for their DD games, which they'll gladly sell you a code for (at what I think are slightly cheaper rates than the boxed copies) in the store. I don't know too much about how it works, mainly because their app is already on my computer (I've had the program since Stardock was running things), so if I want to buy something digitally from them, I'll just do it that way. You tend to get better prices that way anyway, since the sales, as far as I know, don't apply to codes they sell in brick and mortar stores.