It's about this question:
This question is set "On hold" because
Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise.
However, the question does not ask for opinions. The question reads for me like
The advantages of PyPy are X and Y. But what are the downsides of it?
The highest voted answer points out what the downsides are (from personal experience). Not an entirely-opinion-based-post in my eyes.
Why was this question put on hold?
To clarify, I don' say that I agree or disagree with this decision. I just want to know why this question is considered as a not good Q&A format.