That was the most poignant observation ever. Way to contribute.
Seriously, though, besides the minor memory hit of Steam running in the background, what's the problem with it? You sign on to it with your old HL CD Key, and boom, you can get access to all the latest (theoretically cheat-proofed) mods, new patches, previous games from Valve that you can download and install right on to your computer...I just don't see the problem.
Granted, those on 56k connections are screwed...but hey, it's time to upgrade, people.