The benefits are a small fee reductions, a few $100 here a few $100 there, and the vague promise of future benefits, though no specifics are offered. So, the answer is, it is worth a few $100, but only if they are already offering the best rate. It would not make any sense to use them, get a worse rate and save a few dollars up front. The difference in rates would equal thousands of dollars over time.
This program brings up an important theme in real estate deals or mortgage deals for teachers: go with the best rate. While this theme might seem obvious, it is natural and unfortunately common to be lured by "Free" deals or other gimmicks. If the gimmicks didn't work on someone, they wouldn't exist. Always calculate the numbers yourself and see what deal makes the most sense in the long run.
While in general, the deals I highlight on this site are good deals, in some cases it makes sense to skip one deal to make the next one available. Or, more commonly, it makes sense to skip a deal to leave yourself in a more flexible position.