Why is it more profitable than mining with 0% pool?
If they pay more than mine themselves that mean they have losses every time they borrow your rig, isn't it?
It's more profitable because you set the price. You can set it higher than expectations. The renter might be mining some alt coin in hopes of a pump and dump. The renter might be using your gear to solo mine and hoping for a 25
BTC hit. Who knows what prompts their behavior...