The bonus for buying direct replacement fans is that if you decide you're gonna sell the card, it comes with the original fan and can be sold for gaming. I know its kinda doin someone dirty but if it still works fine, and is just not profitable to mine on anymore, you can still sell it at a huge discount to someone who normally couldn't afford to have such a nice GPU for gaming. Even if the lifespan is not going to match up to their expectations, they will figure out thats why it was cheaper than the rest of the same cards in the area.