Why would they want to attack the Bitcoin network with a quantum computer when they can mine blocks using it, but again I guess mining with a quantum computer would still not be enough, but with so much power on your CPU device I guess you can sure do a ton of gaming with it, Well in my opinion I will not gonna use it in gaining bitcoin and destroy the bitcoin ecosystem, That much worst depreciating the price of bitcoin now that it is in the bull run state, But for cryptocurrency sake I guess Quantum Powered Miner will be created in mining blocks for every cryptocurrency and Bitcoin can be possible.
Do you even understand what quantum computing is and why we don't already have it? Quantum computing components need very energy intensive environments to even exist. I can give you an entire class on Q-bits and sub zero containment but all that would seem like a moot thing to do who thinks quantum computers would be invented to play games and mine or attack Bitcoins... that is so trivial.