The main selling point of buying a game instead of stealing it is that you get it quick and easy.
Oddly enough, this is the main reason I buy games on services like Steam rather than buy them in a store. Downloading Civ 5 only took about 38 minutes, during which I was also streaming a movie and I think my girlfriend was doing some other stuff. Once it is purchased, I don't have to keep up with the DVD or the serial key as well.
Personally, I find the main point of buying a game instead of stealing it is that you get the game
legally. Ya know, the knowledge that you won't be hit with a massive-scale copyright lawsuit with a $2000 dollar settlement.
But yes, digital downloads are an incredible thing. I have a filing drawer full of the various CDs, manuals, etc. that I accumulated over the years. There was a time when I was constantly swapping CDs (and often decided which game to play based on what was already in the drive, lazy me!). The only time I've reached into that drawer in the last 2.5 years was once to reinstall WC3. The lack of CDs and connected serial keys
alone is enough to convert me to digital distribution, never mind the automatic installation of patches.
Of course, if your internet is slow and your bandwidth low, I can see downloading Civ V to be a real pain in the rear. So, to those people, I say: "Umm, sorry!"