No, that’s silly. Any body part would have worked.

It’s not only hair that works, though it’s a type of ‘bit of the person’ that is easier to get than most, I guess.

Agreed

My daughter suggested this the other day when we were marathoning the films and I was so proud:

Someone could turn into Voldemort using his spit off a glass he drank from! A Death Eater or a free elf, like Dobby, could easily steal it after he's done and walks away.