Export: So do you hate logging into Windows to play a game? Coming from a console perspective, it's annoying to boot up an OS to then play a game -
Less is more. I'd rather log into Windows than log into Steam
and Windows.
More to the point, I use my computer for a lot more than just playing games. I don't have to turn it on every time I want to play something, and even if playing a game is the first thing I want to do, I'm going to do something else afterwards. My computer is going to be on whether I'm gaming or not, so this isn't remotely an issue for me.
Console-exclusive gamers tend to have computers too, you know.
Export: not to mention installing the game in the first place. A common complaint for many PS3 games is having to install parts of the game first, but this is totally accepted on a PC. Imagine if you could just put a game disc into a PC, turn it on and play the game straight away.
That wouldn't be a good thing. Installation is an advantage, because hard drive access is faster than optical drive access. Given the option, I
want to install my games to the hard drive.
Remember when early CD games commonly gave you options between limited, standard and full installs? Yeah, the limited install was faster and took up less space, but you'd pay for it with longer or more frequent load times - especially for FMV left on the disc, when the game stalled while it waited for the drive to spin up, then started streaming and decompressing in real-time. If I had the hard drive space, I always did a full install.
(EDIT: Oh, and I forgot disc-swapping. Remember that? That -sucked.-)
No-install digital distribution would have the same problem - decompressing data from your downloaded files on the fly - unless games were distributed in 100% uncompressed format, which isn't nice for either the consumer or the distributor.
Plus, if everything is streamed from the disc, modding becomes a lot more difficult.
The only way this would be a good thing is if it were totally optional, but then you're asking the programmers to support both, just because some people don't want to wait five or ten minutes for a one-time installation. In these days of $70 terabyte hard drives, I really don't see the point anymore.