It's intended to give teams incentives to hire black coordinators and assistants. Whether it will or not is debatable and whether that ultimately leads to more black coaches is open to further debate.
I think it's good that the NFL is trying something. Certainly understand the critiques of their exact plan though.
This is a much easier way for the NFL to see if their rule is working, too. With the bigger sample size, you get to see if adjustments are made at the lower levels.
With head coaches, you only got so many per year, and with highly qualified candidates always on the sidelines it made it really difficult to analyze, IMO.
The Ravens are under a bit of pressure here to fill what, 4 or 5 vacancies now, and if they don't do with a quality number of POCs (and nor do other teams) they'll know their rule isn't working in a matter of 2 or 3 seasons.