First off lex Friedman had a really good podcast on this. Quantum computers use a different processor which is specific to solving one problem, a problem which could take decades to solve on today's supercomputers in days or even hours. A classic computer is great at solving many problems but doesn't specialize in any specific one of them. The use case for me that is interesting is the use of quantum computing in solving complex medicinal, biological, and chemistry problems. IE develop new medicines in an extremely accurate and efficient process