Why do we not see Allah, and what is the benefit of that?

Allah, in His wisdom, decreed that no one in this world shall see Him, for several reasons: among them, if He were seen, all people would believe, and the wisdom behind their existence would be negated. Another reason is the weakness of creation and their inability to bear seeing Him.

As for the Hereafter, the believers will see their Lord, and this will be their greatest reward, as stated in the Almighty's words: "Some faces, that Day, will be radiant, looking at their Lord." And in the Hadith, it is mentioned that for the people of Paradise, the veil will be lifted, and they will gaze upon their Lord, and they will not be given anything more beloved to them than that.