FWIW I've been racing cross now for 11 years. For about 7 of those years I had a pit bike. In that time period I did not use my pit bike once. The one time I was close to using it was when I flatted with one lap to go and the pit was on the other side of the course. There was another time I didn't have the pit bike and that was when I broke my stem on the first lap. Pit bike would had been nice there.
Point being, I had the thing, traveled with it, took up bike rack space on the car and space in the hotel room and it never got any use. I just have a spare wheel set these days.