I think it’s hillarious.
I doubt he would end up losing — with a body part at stake… Even then, there’s a good chance he won’t cut off his finger.
It’s just a publicity stunt as others have said before — kind of like those websites that say “Help me raise $xxxxx before (insert date), or the bunny/puppy/kitten gets it!”
If he puts that up on ebay, it will more than likely be shut down as soon as an Ebay representative sees it.