DNG does contain the "maker files", the special sauce that the camera manufacturers embed, but ACR cannot use that in most cases
use the additional information, but the basic position is, that ACR has to deliver the very same result, no matter if from the native raw file or from a DNG without any undocumented information
Thus ACR uses only that data, which can beconverted in standard metadata, be it Exif, TIFF-EP, or DNG.
1. WB can be converted in DNG, so ACR does make use of the WB information, even though that is undocumented,
2. contrast, sharpness, saturation can not be converted; although there are corresponding fields in Exif, they are not suitable as substitute. Thus these settings will be ignored by ACR.
3. Highlight Tone Protection (a flag in MakerNote, again undocumented) is partly
supported, for the adjustment of intensity can be translated, but the initial curve change (which will be done in-camera and by DPP) can not be expressed in the standard metadata.
and niether can the OEM software once it's in DNG
If the OEM software can take advantage of the original MakerNote, then it can use it with minimal effort from the DNG file as well.
DNG also contains a great JPEG embedded, as John's noted
The Adobe DNG converter may
add one or two JPEGs (one medium and one large), in addition to the thumbnail, if the respective option is selected. These are standard in TIFF, most programs can use at least one of them. For example if you open a DNG file with ACR, this preview JPEG is displayed first.