My reason for wanting a pants like these is more for comfort reasons. I agree that a pair of supplex pants combined with a base layer is a more versatile combination, but I have found that these pants are always uncomfortable for me.

The belt digs in, they fall down, etc.

It just seems that a pair of pants with an elastic waist that fit like a pair of sweats might be more comfortable, especially while backpacking where the pack belt always pushes my pants down and jams belts and buckles into my side.

Matt