Oh well the pump needs to be properly lubricated just like an engine does. Power steering fluid additives wear out like transmission fluid does. Some pumps make a lot of noise when the fluid looses it's normal properties, and doing this flush makes it completely silent again. I've done a handful of those.

But as far as how it's assisted, I notice no difference since as far as transmitting force goes, a liquid is a liquid. I just want to keep the pump and rack happy.