That statement alone does not paint the whole picture. It also has to be better in terms of some metric (e.g. accuracy, computation time, size of molecules simulatable) when compared to classical ones.

It makes accurate simulation of quantum mechanical systems of relevance (e.g. molecules) even possible. DFT simulations are full of approximations just to get them to be able to run on classical supercomputers. Nobody does a full solution of Schrödinger's equation. With a sufficiently sized quantum computer, you could.