for the average guy on Sherdog I don't see how this is worthwhile. Either he trains his ass off for months, takes a beating and then spends the next couple of months recovering, or
no training, take a severe beating, recover for several months. All for $25K.
Most people can earn more than that with less work, in less time with no beating, health risks or potential for long-term consequences. An aspiring fighter, however, would probably already be training and would value the opportunity to fight a pro. For those guys, $25K is a great deal.
Personally, I would not want to fight any top-10 HW.