In a hurry? Hoping to look cool? Tied to something? None of these is a good excuse for using teeth to tear open a condom. Latex is a good barrier against semen and pathogens, but not against teeth. Even if it's not visibly punctured or torn, a bitten condom may still be damaged enough to break.
Aside from all of those actual risks, lube can taste gross.
Don't look for anything sharp as a substitute for canines and incisors: Scissors, knives, long fingernails and basically anything else that's sharper than fingertips are also on the "Do Not Use" list. It's a little like that rule about not putting anything in your ear that's smaller than your elbow.
A run-of-the-mill condom wrapper has serrated edges to make it easier to open, and the foil or plastic material tears easily once it's started. It's a two-handed – but zero-toothed – operation. Plus, designers like Ben Pawle continue to come up with easier-to-open designs, like this one-handed condom package, for people who need them.