Apparently he gains by getting lots of visitors to that site.
Also all these things are based on the assumption that long threads about it will result in many forums debating this. That will mean that lots of people will go and watch the match, or whatever, visit the poker site, and the whole publicity stunt will have worked.
Personally I could care less if he wants to chop off his body parts – nuts.
But I just as rather not give it publicity, it’s gross.