1: Easier to make a segment with DH and freeride than it is for XC. Plus XC is a bit like golf, fun to play, boring as all get out to watch. There are some exceptions though, you just have to find them.

2: In some senses rigid teaches better technique, but suspension does help make line selection much easier. Macaskill is a trials/street rider where suspension can be a major hinderance, plus rigid makes a trials/street bike lighter.