My local Wincos had a self checkout, and only have 1 or 2 cashiers open. They used to have two security guards and three cashiers managing the self checkout, with a massive line of people all the way to the back. It was like that for two years.
Today, I visited and they took the whole thing down, while having 5 checkout lines open. No security guards.
Real pleasant experience.
The only self checkout I like is Home Depot. They nailed that thing.
Putting the robust scanner back in its holder is a very satisfying sensation.