It's voluntary and it's a chance to save a life, however unlikely. It's also a complete unknown, which is the most frightening thing in the world.
But it's a step forward for progress no matter what, and I'm glad there are people willing to try this. It could end up saving a lot of lives in the future, and it could increase our understanding how our minds work with the body considerably.
That said, I don't think I would have the courage no matter my condition. Also, just witnessing what could potentially happen to a human being doing this, would be something I'd avoid at all costs.