Oh Bill............... don't pretend you don't know what that phrase means.

it means.. when you help someone else, just for sake of argument.. another songwriter....you both get to have success, so in one sense it looks like you're helping someone else, but in reality... doing something nice for someone else does great things for you.

Because, if you were trying to cross the river yourself............ and you help someone else.. you BOTH get there.

"It Mattered to THAT One"