There are good people who - through no fault of their own - can find no better job than that of a checkout clerk.
I will stand in line for one of those folks for an hour before going to a self-serve line. And if all the lines are self-serve, I will shop elsewhere.
As with most things, your mileage may vary.
The “store” will hire the same number of people. Instead of a smiling and helpful checkout girl, you will get a bunch of baton-waving ANTIFA thugs at the door.
Unintended consequences? I think not.
I prefer to do my scan & bag, else I end up with 15 plastic bags with very little in any of them.
A lot of places can’t find enough workers to staff a human check out line.