Certainly, we can imagine other use cases for quantum computers. But just because something could be useful doesn't mean it will be developed; the cost still needs to be surmountable.
As you noted the problems they pose for cryptography can be addressed with PQC. Military/Defense/National Security invests in them for the cryptographic applications (and probably also for the logistics applications), but they are only about 1/3 of the investment.
The rest is for the doing better physics simulations and for logistics and financial applications. The physics simulations will be huge and drug development and materials science.
A cursory google still seems to indicate people are using these things to learn how a hypothetical QC could be used in practice, rather than actually doing stuff in production or anything close to it.
> Despite the limitations in size and speed of today’s quantum computers, our algorithm provides quantifiable liquidity savings when applied to the Canadian HVPS using a 30-day sample of transaction data. By reordering batches of 70 payments, we achieve an average of Canadian (C) $240 million in daily liquidity savings, with a settlement delay of approximately 90 seconds
It has to be noted that the technology used (quantum annealing) is at best erm disputed, and that the company DWave has made very wild claims in the past. Also note that many "quantum speedups" have been de-quantumized, i.e. classical algorithms with equal or even better performance have been developed, sometimes by drawing inspiration from the quantum algorithm. Quantum supremacy is still quite unclear.
Now, could the problems we are talking about be efficiently solved on a classical computer? Maybe. But if nobody knows how to do it, we might just as well use the quantum computer.