You said it your self "supercomputer" not quantum computer, you could also call ASICboost machines as a super miner.
Since when mining is a crime? no matter with what kind of hardware you are mining as long as you don't skip the work
Only concern about quantum computers is about their ability to crack down the prime number sequence and find private keys not what if they were mining bitcoin.
Already IBM/ DARPA/ Google and US have their own QCs but still in early stages of development, they are now more like the 30 years ago mobile phones which people used to call them bricks because they were big and heavy.