I qualified CMPO, QAI submarines and QAS on two surface ships and it was a valuable learning experience. The majority of the usefulness comes from learning the material storage, handling and classifications. Also being the final reviewer of work packages in the division, for records and closeout files.
Now the part about having any impact on the outside, not really. The education is worth something and it does translate to the similar skills in the commercial world, but you have to completely re-qualify. The good news is you will already understand most of the concepts and be ready to qualify faster once you learn the new adminstrative requirements and the differences in titles. So the training is absolutely valuable.
One thing to note, When I was working in the division as the QAS, the officer in charge of QA for the department would not let everyone qualify, only those that had exhibited not only knowledge and desire to learn but the experience of working in detailed maintenance issues for several years. This was not something that you wanted to necessarily entrust to the new members of the division just to have someone capable of signing documents.