Often, while practicing a piece, musicians have to make a decision on how to play a certain passage in regards to articulation, dynamics, phrasing, rubato, etc. Is asking for a recommendation between 2 or 3 stylistic choices acceptable if the asker is asking about playing the piece in a particular style (that of the composer, of the time period, playing a piece arranged for another instrument, etc.)
There are probably a lot of off-topic (at least in the sense of being unanswerable) questions that would fall under this heading, but there are most definitely many good questions to be asked on the topic, too.
In my opinion:
The bad questions would come down to "does A or B sound more beautiful" — one person might say A, another might say B, and there's no way to decide between the conflicting answers.
The good questions would be about, for example, historical performance practice, or what is idiomatic a particular instrument. There is definitely a lot of room to debate the interpretation of data on these questions, but there is ultimately solid data, not just personal taste, on which one can base an answer.
(For example, different scholars disagree about how many singers Bach had in his church choirs in Leipzig, how many he wanted to have, and how many he'd like you to have — but there's a solid body of information, from written accounts to physical surviving artifacts, and each answer has to analyze those data to argue for its conclusion.)
I would go as far to say as this is Opinion based, but providing that you can teach and be taught new ways of playing and new techniques as a information source I don't see any reason why it would be off topic. Although there maybe mostly opinion based answers as I've said. the fact that there are "choices" when playing certain riffs and so on, people may have their own preferences. but this may help you find the one that right for you thus answering your question, with a little second hand information.