Clotting is good. Being in a state of health where blood properly clotting in response to an injury is dangerous is bad.

I used to get spontaneous nose bleeds too. They started around grade eleven, that's the first time I ever went on a diet, also around when I started working out. The diet was Eat to Win, low fat, very high carb. Sugar-free wheat puffs were healthfood. Might as well have had Sugar Crisp or Cocoa Pebbles for all the good that did me. Lots of cavities, abscessed teeth. I kept getting nosebleeds, right through my teens and my twenties, especially when I dieted, still low fat. I haven't had a nosebleed since I went low carb.