Useful. This demonstrates that coin flipping merely amplifies noise in human manipulation.

A classic example in the old PSSC high school physics curriculum was a little catapult-like device which tossed a coin, spinning it a few times in mid-air, and repeatably landing it on the same side. It's a demonstration that Newtonian physics is repeatable.

Yes, that's because a coin toss is not intrinsically random, but just pseudo-random due to its chaotic behaviour which is especially notable at relatively "extreme" starting conditions.

But if the tosser were to control, manipulate or just don't care enough about adding entropy to the toss, those random generation qualities of the object would start to fall apart.

PS: As I read before, dice/coins are not entropy generators but rather, entropy sinks+processors.