Not in my experience, because the self-checkouts have to be designed for untrusted users instead of trusted employees. So I spend more time reacting to "please

Not in my experience, because the self-checkouts have to be designed for untrusted users instead of trusted employees. So I spend more time reacting to "please scan item" -> "place item in bagging area" -> "unexpected item in bagging area" -> wait for employee to notice that my checkout needs an override. Whereas a manned checkout lane gives me a proper belt to put my items on and someone who can usually operate a terminal fairly quickly.