Pinky used to form A shape partial Barre chords

This may have been asked before but why do most guitarist's use the pinky when forming partial Bar chords and not the ring finger.

I think so they can go to some other frets with the other finger to embellish chord tone..
That's my guess

Probably because it's easier for them - I practiced both way but like it more with the pinky because the forearm is more relaxed that way espacially when fretting a chord near the nut like Bmaj.

It may also be so they can get the high E string to ring. Since your pinky is smaller and shorter, it can be easier to do this with your pinky. I use my index finger because if I want the high E string to ring, I'll use all 4 fingers for the chords rather than just 2.

I've also noticed that a lot of the instructors here will use their pinky with the A shape barre chord.