I believe that it will more or less just burn a data disk of the mix. This would be helpfull if your mix is at 24 bits and you want to send it to a mastering studio (like mine...hint hint... ) so they can use a .wav file for mastering. Go to www.digido.com and read about preparing a disk for mastering to learn what they like to see. I am sure that they are fairly standard when it comes to submitted formats for mastering.
Otherwise, a CD player still only works with 16 bit 44.1kHz sampling rate .cda files on a CD, so if you are burning a disk you want to play on a CD burner, I don't think you need to concern yourself with that other option in your software.