I think there is promise with tons of optimization problems (machine learning, approximating differential equations). I hope these would be significantly faster in practice.
It would be cool if we had quantum accelerated game physics engines. Super realistic games that are fast.
Simulations could scale better, so we could make them a lot more useful.
Unless you are simulating quantum effects, these sorts of simulations are unlikely to be faster on a quantum computer. Also, attempts at using the Ising model for general-purpose optimization have found themselves somewhat limited in application.
For people doing drug discovery and quantum physics/chemistry research, they will see an exponential speedup from quantum computing, but I think you're overstating how applicable this technology is.
It would be cool if we had quantum accelerated game physics engines. Super realistic games that are fast.
Simulations could scale better, so we could make them a lot more useful.