Would Satan have the POWER to cause Jesus to HALLUCINATE?
Since there is no spot from where this would be possible, EITHER Satan caused an hallucination, or the author of "Matthew" just MADE UP a story.
If it was NOT a mountain, why wouldn't the author write that Jesus was SHOWN a VISION of all the kingdoms?
Why pretend there is such a mountain?
Imagine that an "ALL-KNOWING" Superbeing is inspiring a book. This Being KNOWS the Earth is a rotating spheroid, and KNOWS that unbelievers will be looking for evidence that WHATEVER inspired this (and other ) passages, was NOT a Being which KNEW about the shape of the planet. Why not "inspire" the authors and translators and copyists to get provable physical facts reported ACCURATELY???
The inaccuracies certainly seem to indicate the book was made up by people.