As stated, the quoted sentence above says nothing; it has no content because of the caveat. Let's simplify on the way to dragging reality back in:
"Self-checkout is fast, efficient, painless. and generally pleasant."
I have never ever seen an implementation that makes bulk goods checkout, as is required for say vegetables/fruits/grains etc., "fast, efficient, painless, and generally pleasant." How could it be? You have to look up each item on a stupid touch screen, weigh it, and bag it. Lots of potential for callous mistakes that are annoying as hell to fix, so I never fix them, and now I'm a criminal.
Ok, so now they're bagging up the bulk goods so they can barcode the batch, and... I get to buy 3lbs of zuccini, with a bad one visibly lurking in there, or nothing.
Awesome technology thanks bros.