The only racing I’ve ever done is Gravity Enduro style events. That’s because they are currently the only type of event that appeal to me. They are similar to the kind of riding I normally do i.e. a weekend away with one night in a B&B (no time off work), two days riding, spin up the hills, bomb down them, beers Sat night, home Sunday evening. Most important: technical, fun courses and plenty of banter.
Those who have commented about “ex-Pro downhillers”: sure they are in the race. That is one of the good things about them. Racing on the same track, in the same race as the pros. You can’t do that in many sports! However they are in different categories to us mere mortals. You actually race your peers.
As for 24 hour events: not my cup of tea. I was race mechanic for some mates at one once and can’t see the attraction in lapping non-technical trails in a state of sleep depravation and festering in a tent between laps.