Why are my cables balanced ?

I am very new to the hi-end audio scene, and evidently don't know what a 'balanced' cable is:

I was in an audio store looking for 1m cables to run from my new DAC to an amp that I am going to get from someone. The guy was trying to sell me 'balanced' cables with RCA ends. Since the DAC has an 'unbalanced output' and the amp doesn't have 'balanced' XLR inputs, what is the advantage of using a 'balanced' interconnect cable?

I have read a bunch of white-papers but don't really understand them. Perhaps someone could explain this easily!

STAY AWAY FROM THIS DEALER. If he was truely trying to sell balanced RCA than he was trying to pull something. 'XLR' make a balanced connection, but only if your equipment is truely balanced internally. I would suggest talking with a different dealer, ask him about balanced RCA cables and see how he reacts. Unless I'm missing something I would not trust the guy you talked to! J.D.
I might not be as vehement as Jadem6, but I'd say that the guy at the shop should know better. ...Is this guy a junior salesman or one of the head honcho's? If he's one of the top dogs he's either stupid, dishonest or both. For a fairly simple explanation of balanced go to the following URL http://www.balanced.com/faq/balanced.html. This should provide you with the information you need.
I would just add that just because a component has balanced or "XLR" inputs and outputs, it doesn't necessarily mean the component has truly balanced circuitry. In fact, if I had to guess, I would say that the majority of components out there with such inputs and outputs, aren't truly balanced in terms of their circuitry.
Sometimes the same cable could be used as either balanced or single ended - i.e. it may have 3 conductors in it, but the shield is just hanging loose in the RCA connector - it is only really balanced if it has an XLR connector. In a real balanced cable with XLR connectors, the signal is carried on 2 conductors, and the ground is the shield. With single ended connectors (RCA) the shield may be used to carry the signal, or if there are 3 conductors, then the shield may not be connected to ground at the end of the cables, its just hanging loose, and the signal is carried on the other two conductors.