Wrapping it around your arm stretches and pulls at the inner cabling. It isn’t a single massive copper pipe in there, its numerous thin guage copper wires wrapped around each other. Wrapping it around your arm puts kinks and folds in the cable that eventually snap those little wires over time.
Over over puts multiple same direction twists in the cable. Over under puts a twist, then puts the opposite twist, so you don’t have to unroll the cable (or otherwise remove the twists).
Wrapping it around your arm stretches and pulls at the inner cabling. It isn’t a single massive copper pipe in there, its numerous thin guage copper wires wrapped around each other. Wrapping it around your arm puts kinks and folds in the cable that eventually snap those little wires over time.
Not the arm one, but the way before that. Over-over.
It also prevents cables from coiling up. Cable that has coil form is the most fucking annoying thing to work with.
Over over puts multiple same direction twists in the cable. Over under puts a twist, then puts the opposite twist, so you don’t have to unroll the cable (or otherwise remove the twists).