I bought one last year to take on a tour, just as an insurance policy. My LBS guy seemed a little confused, but I figured I wanted something easier to carry.
Any other reasons for folding tires? It seems that's the only kind that exist in the Continental Ultra 2000 that I love... so I'm getting one anyway... maybe two... or three, 'cause I don't want to be two tired to ride... but I was wondering what the deal was with folding tires unless people are like neat freaks.