I don't condone theft... but I do remember a day before self checkouts existed, and stores had to hire enough cashiers to be faster than their competitors. Those dozens of checkout lanes at the front of big-box stores weren't always decorative, they used to all be staffed during busy periods.
Why am I waiting in line to check myself out? That is what drives me nuts. "But they take up space" you say. There's lots of wasted space with the 8 standard checkout lines that are unmanned every time I come in the store.
I have never experienced a faster checkout with self checkout.
If it's super fast, it's just for a few items, and a cashier would've been just as fast. If it's for a lot of items, there's a decent chance I have to look up some codes or something; which a cashier is better and faster at.
The trade off of self checkout is cost savings for the business. These savings are not passed on to me. Therefore, I don't give a flying rat's ass about them.
I'm with OP. If I'm working for the business, they will compensate me. Willingly or unwillingly.
IME it's faster because the queue is shorter. You can fit about 2.5 self checkout machines in the same space, enabling more people to checkout in parallel.