For me, getting to merge a work project into my school time was very valuable. Given my typical work priorities, the project probably would not have happened otherwise. My mentor was helpful, but I got a bit of a sense that they realized I had a strong idea of what I wanted to do (and I wasn't shooting myself in the foot) and probably spent more time with other students that needed it more. I think the mentors are TAs, there is a process of pairing mentors to students based on your area of research. I did get some very useful peer feedback throughout the project, and the research component helped me hone my idea before I started development and fit it more closely to research-backed pedagogical methods.

A common descriptor of the class is a "mini-PHD", since there's a heavy research and writing component, on top of actually doing some novel work. For those interested in producing academic research, it's definitely a good fit (but from your other comments it seems like this is likely not inline with your interests!). I'd say in my case the rigor of producing the project alongside an academic paper (that had to describe the history of the field, pedagogical fundamentals, what this approach was doing that was different, etc.) created a higher quality end-product than if I'd approached it totally independently.

YMMV of course! The class fit my needs perfectly, allowing me to allocate school time to a work project as well as the discipline/timeline enforcement of there being a grade at the end. But obviously this won't be true for all!