Your brain will completely tune the beeping sound out after a certain point, if it's a thing you notice at all. Similar reason to reversing truck beepers being

Your brain will completely tune the beeping sound out after a certain point, if it's a thing you notice at all. Similar reason to reversing truck beepers being replaced with ones that produce white (or other coloured) noise, so you don't lose your ability to hear where they are. It's hard to believe until it happens to you.