Or they live in a second/third world country, or they're a student, or...
I wouldn't take this deal, because stopping / starting employment isn't that easy for me, but I can see other people rationally taking it.
And if other people think he's underbidding, I would encourage them to bid him up.
But for those people who freelance, and are in between jobs this may well be an ideal opportunity to (continue) being paid for doing something they have been thinking about for a long time.
It's okay if you don't hit a home run. It's even better if you don't starve or get evicted for your troubles.