Why did Prophet Muhammad take such a long distant journey?

Even though Allah the Almighty is closer than everything, why did Prophet Muhammad take such a long distant journey?

One of the contemporary scholars of this time Bediuzzaman Said Nursi responds this question in this way:
“Allah the Almighty is closer to everything than any other thing. But everything is infinitely distant from Him. For example, if the sun possessed consciousness and the power of speech, it would be able to converse with you by means of a mirror held in your hand. It would have power of disposal over you as it wished. Rather, although it would be closer to you than the pupil of your eye, which is like a mirror, you would be approximately four thousand years’ remote from it and could in no way draw closer to it. If you progressed and rose to the position of the moon and came to the point of being face to face with it, you would still only be able to be a sort of mirror to it.
In the same way, although the All-Glorious One, Who is the Sun of Pre-Eternity and Post-Eternity, is closer to everything than anything else, everything is infinitely distant from Him. (…) For example, a private is far beneath the rank of the commander-in-chief. He looks to his commander through the small sample of his commander’s rank he sees in his corporal at a great distance and beyond many veils, as it were. To attain the true proximity to his rank through his corporate personality the private has to pass through many universal degrees or ranks, like that of lieutenant, captain, and major. Whereas the commander-in-chief can be present with the private, and seeing, in person as well as in meaning, through his commands, regulations, view, decree, and knowledge.
Besides, this following verse points that the earth and the ones in it do not have the capability to bear to the manifestation of Allah without curtains: “And when Musa came at Our appointed time and his Lord spoke to him, he said: My Lord! Show me (Thyself), so that I may look upon Thee. He said: You cannot (bear to) see Me but look at the mountain, if it remains firm in its place, then will you see Me; but when his Lord manifested His glory to the mountain He made it crumble and Musa fell down in a swoon”. Commenting on this verse, Elmalılı Hamdi Yazır (an interpreter of the Qur’an) says: “It can be concluded that Prophet Musa could not bear and fainted because of being exposed to an direct manifestation of Allah which happened through a mountain. If there had been a complete and absolute manifestation (if Allah’s personality could be seen) the entire world and perhaps all the universe would have been annihilated.”
In short, we can say that the beloved Prophet (pbuh) was ascended to the Miraj to attain a post which would enable him to meet Allah (SWT) without barrier and to be shown the realms which were related to his prophethood task.