Not being able to explain, though, is another matter, and it mystifies me why adults sometimes seem to admire this (not you necessarily). It's actually the explanations that are the maths, tbh. I wouldn't count a question as answered unless the child can explain why the answer is correct. That doesn't have to mean "show your work" in a tedious way. It can be more useful to play an "I don't believe you" game - push for a gradually more elaborated argument by questioning selected steps. If there's really no explanation available I'd reframe the answer given as a guess: "OK, so you guess the answer's going to be ... Let's see if we can work out whether you're right."
My son needed more than we would have been able to accomplish with an "I don't believe you" game. He needed a systematic teaching of the language you use to explain his thinking. He has clear language quirks in his development, so it did seem like a necessary intervention.
Recently he told me that he takes a problem and knows the answer, and with the language stuff his teacher taught him, he goes back and translates it into steps. He does this for things no one ought to be able to do in their head, and it doesn't see like he's working it out in his head, but he knows the answer somehow. He could do this for a situational problem before he even knew what the words "multiply" or "subtract" even meant. This might be an elementary/odd form of intuition -> conjecture where he needed to be taught the language of a proof.
I guess my point is that we've seen a lot of positive out of directly teaching "this is how you justify your intuitive result."
