Advantage over DTS encoded CD's (Score 1)

Having played a number of DTS 5.1 CD's on my plain old regular CD player, I've found the 5.1 sound to be a big leap from standard CD formats.

I'm assuming the advantage of DVDA is higher resolution or less compression but I've not seen anyone compare the quality of those two formats. It always seems to be DVDA vs. CD.

Since the DTS CD's play just fine in 5.1 without extra equipment and they are becoming more available, what's the delta that makes DVDA a better option?