I asked this question and it was closed as off-topic. Is asking a question on English usage which is obvious for native English speakers but not so for English language learners off-topic in this site?
Yes. There is a separate Stack Exchange site specifically for English Language Learners (here), and we try to maintain the distinction between the two. In addition, as the explanatory text says, a question that can be answered by consulting a general reference such as a dictionary is out of place here. It is true that many such answers can only be found if you know where to look; but in this case you had already been given the two phrases 'matchbox' and 'box of matches' which are quite easy to look up.
If you ask a question (as too many people do) about "which is correct", then, yes.
That's not what we're here for.
If, on the other hand, you ask something that is about English Language and Usage, then you may rest assured that it is not "obvious for native English speakers". This is because native English speakers who are educated in Anglophone schools are not taught about English grammar. Instead they are fed a bunch of mythology about tenses and cases and correctness and not writing like you talk.
This means that pretty much any native English speaker is the wrong person to ask about English grammar, because they never learned grammar in school -- though they speak English, of course. Thus they have a lot of quaint ideas about it, none of which are true or helpful, but all of which are firmly believed.
I have seen no real difference between the two groups; both are staffed by volunteers, and many volunteers have the idea that English grammar is a matter of opinion or of law. Both ideas are false.