Quantum computers are binary. “Wave functions” are functions. A function is a mathematical object, not a physical object. Why is it only in quantum mechanics that people try to reify functions as entities in the world? Quantum computers contain bits and those bits only contain a single bit value at a given time. No one has ever observed a quantum computer to ever contain anything else. Those values just change in a non-classical way. The deviation from classical physics is in the nomology, not the ontology.