Except that with the Steam model you download a copy to your local hardware - and you can re-download it onto any other hardware whether you own it or not as long as you're logged into your Steam account. The online servers basically work as a perpetual, access anywhere backup.
For instance, I own Shogun 2: Total War - my mum doesn't. If I'm visiting my mum I could, if I wanted, log into my Steam account on her computer download S2:TW and play it there.
But, yes, I still sometimes prefer the physical media and tend to buy CDs... but for games, well, there probably aren't that many games that you'll want to still be playing that you bought 10 years ago, let alone 20 or 40... and, as far as I'm concerned anyway, I think the pros outweigh the cons when it comes to Steam (especially when they have one of their sales on and you can pick up games dirt cheap; the original Mass Effect for £1.75 before Christmas for instance).