Why do you care? I thought that they are all 'great' this days...
I would certainly not say such a thing. There are still poor DACs hiding in various places, such as the headphone jacks on some CD ROM drives and some portable CD players with electronic shock reduction.
Obviously, all DACs are not great, but a large proportion of them are great sounding. This contrasts with the audiophile myth that anybody can run off to an audio store and sort DACs by sound quality in the same way that one might sort different colored M&Ms.
The up converting described in that ad no doubt relates to the video, not the audio.
The nature of the real world problem that this cheap audio system addresses is that the video scalers on a lot of HDTVs are limited to non-existent. In some cases a non-upscaling DVD player will only display a small picture in the middle of their screen.