From what I understand, and from the 2 or 3 DNP recipients I have met, it is being used more for nurses working in higher administrative roles and university faculty positions. There's no more advanced license for nurses right now than the APN license - the DNP is a degree that confers no more clincial rights than getting your APN license. It does not allow a DNP to practice independantly as
an MD does, the individual states would need to change those laws.
Nurses are getting to that level already with the PhD degree - and I forsee the DNP being used in the same manner - by nurses wanting to do higher-level research, those wanting to teach at the university level (most colleges require a Doctoral
degree to teach at the Master's level - and both the PhD and DNP are doctoral degrees), and those in higher-level administration.
Here's some pretty good FAQ/info about the DNP role and education: https://www.aacn.nche.edu/DNP/DNPFAQ.htm