Bagboys will save you a good 10 minutes at checkout, since you don't have to worry about bagging your stuff properly; they sort food into the proper bags so that everything that needs to stay cold stays cold, no raw meat with other things, etc.; and they're almost exclusively high school kids that need a job so that they can pump cash back into the economy buying things like music and DVDs.
edit:
ay ay ay
but it also means labour is cheap and there's not a too solid employment rate?
what are you talking about. the existence of a single low level job in american supermarkets/department stores does not prove anything other than that american employers have decided keeping the position is financially beneficial.
it's not like these guys would be doing anything that pays more if they weren't working as bagboys. they'd either be working at mcdonald's or not have a job at all!
do you not understand how labor works or are you just using this as another example to deploy your ceaseless eurocentrism? because you know, europe has low level jobs too (the existence of BAGBOYS is incredibly insignificant in the overall economy and there are plenty of cheap-ass jobs in europe too! if you guys don't have bagboys fine but it is equally likely you have low-level positions that aren't in existence here).