why do some 4A players do this?

I have noticed that some 4A players have used a glove on thier off-hand.
why do they do this and what would this benifit?

When you play offstring, your yoyo will shoot in the air, then your hand rushes across the string to grap the end and catch the yo. That causes friction and burns. It’s also good to have a glove to wind up the yoyo.

Offstring has lots of string gliding across fingers.

The “Grind on Palm” is also pretty common.