This a hundred times. Comments should always be about intent; never about what's actually happening (the mechanistic description). I don't need help understanding the code as read; I need to know WHY the code was written. So I can debug, follow code paths, skim.
A further advantage: such comments have longer halflives. A rewritten method may still have the same purpose long after all details are changed.
A further advantage: such comments have longer halflives. A rewritten method may still have the same purpose long after all details are changed.