Quantum technology is a science. For now. Temporarily, but time is known to always go fast.
I think people can make quantum computing available to everyone, they can make a personal quantum computer. I suspect that inside this miracle of technology there will not be a system of cooling the substance to zero, but technologies to conquer magnetic fields for the same purposes, which, as the scientific press writes, are developing.
I do not see a solution to safety problems for the user, even if these technologies are available, even if they are absent.
I'll explain why.
What will break a quantum computer is cryptography.
What kind of cryptography would a quantum computer attack? Asymmetric, from the last century. All modern post quantum asymmetric and even the old symmetric AES level, let alone the Two Fish, will never be attacked by it.
Why do I say that so boldly?
Because today's old AES-256 is perfectly capable of handling the quantum threat, the foreseeable future. To extend the key length to 512 bits is worth nothing. It's not gonna put much strain on the processor when it comes to encryption. But for quantum computers, increasing the key length from 256 bits to 512 bits is absolutely impossible to improve this technique in a reasonable period of time.
From the scientific point of view - the world of numbers is infinite and to use this resource, you can increase the field of numbers for encryption instantly. But to improve the technique that will catch up with the "infinity of number fields" is a difficult and time-consuming task.
In fact, even modern cryptography is never broken, keys, passwords and information are always stolen. The same will happen after a quantum computer is available to everyone. Nothing will change. We will also be attacked by ourselves only by compromising sensitive data.
Why do you need a quantum computer to attack a bitcoin - I don't understand at all. Even the old asymmetric cryptography on elliptical curves, with a 4-fold increase in the length of the key - will remain a dream to crack the known algorithms on quantum computers.
Everybody looks the wrong way when they think about security issues.
There are billions of accounts on the darknet that are sold for nothing. We are all hacked a long time ago, and so we will in the future if we keep the old key encryption technologies and password (and biometric) authentication methods.