Nope, the only advantage to self-checkout is you don't have to interact with the normal checker and generally is faster. Assuming, of course, everything you're buying has a proper UPC tag and the scanner is working properly. And you don't have anything too big to fit on the scale (the little bag holder thing has a scale so that it makes sure that you put everything you bought into the bag, and that you don't put anything in the bag that you didn't scan) etc...
I use it maybe 25% of the time, because it really is faster than going through the regular lines, but only if I'm not buying anything (wire, hose, etc.) sold by the foot and don't have anything bulky.
nate