There are a few reasons that disc brakes are superior. First of all they dont scab up your expensive rims. Disc brake bikes can take advantage of lighter stronger and more aero rims since they dont need a braking surface. Disc brakes are pretty much unaffected by water. Then too there is the fact that disc brakes dont heat up the rim and tire on long fast down hill runs. In a few cases it heats the rim and tire so much, the tire blows off the rim.

And lastly it pretty much makes no difference if you like them or not, it is what the mfg are putting on their bikes, due to economies of scale.