While I did not apply, I can see the appeal. In one word: Adventure
A week was enough of that for me. I'd still like to visit Mars, but I can't imagine I'd enjoy living in those conditions for the rest of my life.
But the polar vortex we just went through was other-worldly cold. It was warmer on Mars much of the time that week. Stores and schools were shut down. The man in that video would have experienced frostbite if not death from exposure.
Large parts of adventures are basically boredom in poor conditions.
Edit: It also needs humor.