1. A good reason for tubulars is just tradition. If you love the gluing and the folding and the look, that's good enough. Tufos don't provide this.
2. The reliability of tubulars seems exaggerated to me - they're slightly less susceptible to pinch flats, probably more susceptible to punctures. Tufos appear to have an advantage here.
3. The "riding on flat tire" thing is way exaggerated - maybe you won't ruin the rim, but you won't have any traction. I've ridden on a flat clincher cuz I didn't have any other option - didn't ruin the rim on my urban bike; I probably wouldn't have tried it on my light rims.
4. I don't know what the ride quality is like with the Tufo beaded tubulars, maybe that's a reason to like them.