I am aware that ceramic coating is very thin (1 micron) but at the very least it keeps the car looking good and makes it much easier to clean.
people over think it. you are too if you're quoting coating depth. Just think of it as a longer lasting wax. You wouldn't expect a wax to protect from rock chips, and neither will ceramic coat.
It will help with bug guts, tree sap to some degree. Chemical damage.