I don’t like that all of the questions are mandatory. For some of them, I just haven’t done enough with whatever it is to have an opinion and would not be able to provide good data.

I don’t know, but I also don’t think you should. They are one of the few reasonably ethical platforms so unless you truly can’t afford it or have an ethical reason I don’t know of I would pay. They do occasionally promote proprietary software but are still far more ethical than any other platform.