My piano teacher started using this curriculum for her students. It is a review for Music Theory and ear training, along with some other things (I’m still trying to wrap my head around what it is all about).
I am a student teacher, and most of the students I teach are in the MTAC program. It runs from preparatory level to level 5. To pass each level, the student has to pass a battery of tests and play a solo piece (or several). The testing can be done at a College with all the parts of the tests done at once (Plan A) or done over time, judged by an accredited MTAC instructor (Plan B). Since my students are working on this, it is important I am part of the program as well so I know how to help them.
This is something I am enthusiastic about doing, because it would be some formal recognition of my abilities. I’ve been playing the piano for a long time, but I’m no Mozart unfortunately 
. At least with the MTAC program, I could get some idea of what ‘level’ my skills are at, and if I moved on to teach at another music store, I could put on my resume the levels of the program I completed.