Why? To maintain capitalism as something we can pretend is viable for one more generation, just long enough for you to die before you might have to change?
...Seriously? This is your defense? Do you for some reason think that if we all used the self-checkout system that capitalism would vanish? Is OP the one at the helm of whether or not capitalism lives or dies? It all rests on his shoulders, not the status quo or the endless pursuit of profit by billionaires and politicians?
If supermarkets were autonomous, you'd be homeless living in the ally next to them, capitalism alive and well.
Do I think self checkouts are the one thing stopping capitalism? No. But I do think it's going to have to get a whole lot worse before things change. We need all fast food workers, all wait staff, all grocery workers, all packaging workers to lose jobs. Needs to be impossible to ignore.
All that's going to do is pull employees from other areas of the store when it gets busy and the rest of the time they will have like 2 cashiers. Even if they did switch back to registers they won't hire a significant amount of people.
When I worked at Walmart I absolutely hated being sent up to the register. I hated talking to customers and I didn't like that it took me away from finishing my job and my manager would argue with me about why my area wasn't done when they sent me up to the register for 6 hours and therefore did not have the time to finish my work.