Depends entirely on the self checkout system in use. My local Kroger has a system that’s absolutely awful to use. Seconds between placing an item in the baking area and the register acknowledging it, and if you scan another item before it’s weighed and acknowledged it’ll yell at you. A few times of that and an associate has to come by and unlock it.

Most of the ones I’ve used at Walmart will handle me scanning and bagging as fast as I want for the most part.