Weight distribution and jiggle control is something I can’t relate to though

It’s not hard. Put on a really heavy backpack and leave the straps super loose, and go try to move around, maybe a few athletic moves that involve changing speed or direction. Compare to a tight backpack with a waistband and shoulder straps properly strapped to your body, and try to move around again. The straps help control the extra motion so that you’re in better control.

Or run around in shoes 5 sizes too big. Or go for a run with your arms loose and intentionally left limp, swinging around like pendulums.

The whole world has a million examples of why providing bracing and support makes for more efficient and comfortable movement.