I don’t know if this thread is still active, but just in case I wanted to point out one of the main issues I have when rendering from the compositor, which is that the file output node does not output cryptomatte metadata in a useful way (it all gets mushed together into a single channel, and becomes unusable in 3rd party programs such as nuke).
I also wanted to point out to this thread that I opened a while ago about how to make the passes’ naming more flexible and practical (in my view), that I think may be of some use here.
Anyway, I hope the compositor gets some love! It has a huge potential, but unfortunately it lacks a lot of optimizations (and features that are mentioned here) to be as a production-level tool.