500 plus fighters on the roster. Losing fighters who may be on the way out or newly signed fighters have to fight somewhere. Better non televised with unknown commodities.
Keeps fighters working, around 100 per year give or take.
If a card has a few cancellations the last week it will still be able to fulfill TV and PPV obligations. Add to that one bigger fight on the card gets hurt or whatever a fighter already trained and cutting weight may be able to replace and move up. Think of it as a bench warmer or insurance.