Originally Posted by Brian Ratliff

Two reasons: it's low pressure and it's clincher. High pressure is to deal with the g-forces; at a full sprint, on a steep track, you weigh close to double since you are pulling nearly 2g acceleration. It also decreases rolling resistance because, unlike on the road, the surface is pretty smooth; higher tire pressure yields lower rolling resistance in this situation. A glued interface is better than clincher because, in the event of a flat, you have a prayer of staying upright long enough to come to a stop. No prayer if the rim is allowed contact to the track surface, which is automatic in the case of a clincher.

Ride what you like, but I'll take my 150+psi tubulars over any sort of clincher, tubeless or tubed, any day.