In all likelihood what they're selling is a code with a disc included that has a basic install to save you the bandwidth. Like Steamworks PC games.
I'm primarily a PC gamer and the transition o digital has been great for me.
I have 3 steam installs, and I freely download anything I want to any of my boxes. My saves are there waiting for me. I have all my friends on one list. I get great sales from steam, amazon and other retailers.
PC has more piracy than any other platform. Yet PC gaming is getting solid growth and it's tough to find PC gamers who bitch about pricing or steam Drm anymore.
And look at big picture mode. The cleanest console interface out there. Needs some work, but I'll take it over the other guys.
If MS and Sony are going to a steam model most will scream bloody murder like PC gamers did when steam launched, but in 5 years? You may be wondering why the switch was held off as long as it was.
Just remember, Valve isn't publicly traded. This distinction will have applications on their way of DD(Just look at Origins or UPlay).