I suspect that outside a well controlled environment (like that small tunnel with a lot of cameras), image recognition still yields too many false positives and false negatives to be acceptable compared to scanning a bar code (then again, maybe scanning barcodes is what that tunnel does rather than image recognition).

That said, there was this whole idea of using RFID tags on products so that checking-out was merely passing by a scanner with your filled trolley - which would scan all of its contents at once - and paying (or even have your card directly charged).

However I believe this failed to take off because neither product manufacturers nor the stores wanted to spend the few cents per box that would take to add the RFID tags.

So in order to save the few cents per-box that would enable pretty much instant checkout, we have these crap self-checkout implementations were clients get to do all the work of cashiers in a teller which is worse than that of cashiers, and without even getting a discount for it (actually prices just kept going up) - the whole thing is fucking insulting.