Businessmen are really vicious. They know how to take advantage of people's greed. Even if a contestant managed to defeat ten enemies, they might still be defeated in the final round
The arena would surely arrange for a strong defender or even sabotage the innocent contestant so that they wouldn't win. In this way, even if the contestant won ten rounds and made quite a bit of money, they would still be forced to surrender it all to the arena if they become too greedy. But of course, the arena would still let some contestants win from time to time. If not, who would even come and fight here if they can't even win a huge amount of money?
Even though a lot of people know how hard it is to win the finals, it would not be easy to resist the temptation of winning a hundred thousand credits if they are Level 3 Mystics. This is a 20 times increase in the registration fee and quite a large sum already