[scheme271]

The author is wrong about cyclocross. I think people riding cross, wanted disc brakes to get wider tires and much better braking. If you've seen pictures of cross bikes after a race, cantilever rim brakes tend to get caked in mud if it's wet at all and they tend to lose a lot of power because of that.

As sonmeone else pointed out, disc brakes let you use wider tires which give you a smoother more comfortable ride whether you're riding a road bike or a commuter bike. Also disc brakes automatically adjust for pad wear so there's less fiddling around once the disc brakes are initially set up.