Harry Houdini reportedly taught himself to tie and untie knots with his toes. That was useful in his line of work. He was said to remove his shoes and socks to practice knots when he got bored at parties.
The ability to wiggle your ears or wrinkle up your nose can be useful for adjusting your glasses when your hands are full.
Nose-twitching is useless for most of us, but it got Elizabeth Montgomery a nice job.