Obviously it is happening for the money, that is why the organizers always pick the best rivalries or popular people so they can sell out completely and also get more money from the sponsors and you know the fighters also getting paid in millions so just like any business this uses the human excitement to make money.
I don't like to bet my money against this type of sport, they are sometimes just based on entertainment and the final say from the anonymous decision makers, they know how to play their cards and know who to favour in most of the matches, this is something you cannot do in football because you can't manipulate 11 players on the field or tell the strikers and wingers not to do their job but boxers are just different. Kamaru Usman and Anthony Joshua's last match came to my mind, who would have thought Kamaru would fall down helplessly like that and most people thought AJ will do anything to retain his champions belt.
It is indeed not worth to place bet on exhibition matches, as you have no idea if they have prior arrangement or not.
As mostly, they are after for their possible paycheck, it doesn't matter if they really did train hard or not.
Most promoters are looking for how will the popularity of their boxer can gain more viewers or buyers of their ticket.
Because after all, it is only an exhibition match and no belt is involve. So what else they would be after here?