Naw, Sandman. Even people who don't have an okay voice (and there are few such people) can sing around the house and in the car. Or the shower. I'm thinking of benefits of such singing:

It encourages good, deep breathing.
It sends air in and out of the body from the bottom of the lungs to the tops of the sinuses.
It stops unhappy thoughts for the while.
It stimulates the brain and brings back memories.
It makes boring chores go faster.
It pleases loved ones.

Who wouldn't be happy to hear a relative who has been sick for months now singing in the kitchen?