Most Physical PC games tend to have a CD Key, which you then activate on Steam/Origin/uPlay/Battle.net and can download the game rather than use the optical disk if you lack a disk drive.
I was talking about the times before Steam. If you wanted to play AoE2 on a LAN party you only needed one copy.
Something like that isn't possible with the share function on steam, it's limited to one player at once.
Also you have to admit that the DRM on physical console games isn't as bad as on steam games. the DRM doesn't make it a pain in the ass to resell your games.