if people would only go to the self checkout when they had 5-10 easy things, then yeah, no probs.
but people with a full cart will go to one, and with that tiny bagging area they are constantly having to hit the "skip bagging" button, and after every 4-5 items they have to wait for an employee to key in a password to continue.
or people will scan something and want to challenge the price, so you have to wait for someone to come over, they gripe, etc.