Nothing on my tractor yet. The company that makes the loaders puts it on automatically because they offer a variety of implements for the loader. The bucket drops off like a skid-steer with 2 pins and they have brooms, augers, angle plows, a backhoe (front hoe?), hay forks, forks, etc... that attach. He gives the 3rd spool to operate any of the hydraulic motors/rams on those implements.
I'm planning to build a log splitter that I'll run of the 3rd spool right now.