The 1926 Schrödinger equation was originally intended to resolve the subatomic quantum particle in an infinite potential field without a word about superposition. Furthermore, E. Schrödinger himself first opposed quantum superposition in his famous paradox "A cat in a box".
However, the giant N. Bohr came with his quantum superposition in 1928 to the Copenhagen conference and announced that he, including himself, who claims to understand it has understood nothing or that he is only a “simple liar”.
We assume that quantum superposition actually solved both atomic chemistry and physics, but this remained a theoretical mystery until the advent of the double-slit interference experiment of a coherent beam of electrons . It has been experimentally proven beyond doubt that quantum superposition exists and works in the same way as described in N. Bohr's interpretation.
The always seductive question arises:
Why is quantum superposition an effective and essential irreducible tool?