Answer:
The difference is in terms of audio quality since the DVD-Audio format has 7 times more storage capacity then a regular CD-Audio.
This means that you can actually hear the audio content on a DVD-Audio the best possible way ever since both the sample rate (192kHz) and the bit depth resolution (24bps) are higher then a regular CD-Audio (44.1kHz, 16bps) and would actually exceed the human hearing capability.
On a regulard CD-Audio instead you have to adapt, in a way, your hearing to a "lower quality" compared to the hearing system.