And the answer is "where else are you going to put them?"
But seriously, it brings focus to the area you are working and stabilizes you.
or,
It stabilizes you and brings focus to the area you are working.
Keep your quit focused. Put your hands under your butt if you have to.
Stabilize
Focus
quit quit quit!
https://www.youtube.com/watch?v=ewWBGNntOb8