You should still view anything Quantum as early R&D.
and what are those applications?
- breaking a lot of traditional public key crypto (this gets a lot of attention, but its not that big a deal because there are alternatives)
- in theory i guess quadratic improvement on unstructured search. I think its unlikely to be practically relavent.
Of course, the plan is by the time quantum computers become capable of breaking those algorithms in practice, the industry will have moved to post-quantum cryptography algorithms.
But there will still be legacy systems which haven't, and also encrypted data recorded in the past in the expectation they'd be able to decrypt it in the future.
