I thought the same, but it turns out unicycles are safer to fall off than a bike. When you fall off a bike, one of your legs is usually caught on the wrong side of the top tube. When you fall off a unicycle, there's no top tube to entangle your legs, and it's much easier to "jog off" like nothing happened. Also unicycles are much slower.

The one time I tried riding a unicycle, I couldn't even get on it sufficiently enough to fall off.

I found that I could land cleanly about 95% of the time, but the other 5% I would (e.g.) trip over the pedals and launch the unicycle off in some random direction. Luckily it never hit anything expensive.

Makes sense.

I practice balance on the Bosu. I've only ever actually fallen once. Usually I can just step off, no harm.