Someone up there said "If it slides, grease. If it rotates, oil"
My Grandpa always said "If it slides, oil it. If it rotates, Grease it"
They grease roller bearings and wheel bearings do they not?
Course Grandpa from time to time dramk a little whiskey for rumatiz, it never cured it.
Really though with todays mixed metals in the frame and a different one for the slide, that creates other problems. I use Lubriplate or wheel bearing grease.
I think the .mil says to grease rolling things in rifles.