Quantum Computing Threat to BTC... Correct me if I'm wrong

[panganib999]

Quantum computer is expected to have the capability to break a 256 bit encryption within seconds. However, it has not yet become a reality, only a certain degree of it have been achieved!

Now, I would agree to the point you are trying to establish! Having an weapon doesn't always mean it will be misfired and used against the humanity! So even if the quantum computer is built so capable enough to break the encryption of bitcoin network, it is least likely to be used for this purpose!

Although it was expected to crash bitcoin's privacy and security, Until now, not a single move was done against bitcoin, IBM's latest quantum computers are just about to be launched around October and it was said that this isn't the fastest computer  that will ever be made. The fastest qunatum computer that is existing so far is the one that Google has developed and is said that has the quantum supremacy. despite of it's existence, not a singke damage has been done so there's nothing to be worried about.

[qubitasic]

the first Quantum Computers will be very few and owned only by large governmental or private organizations, until technology advances to the point it could reach the masses

They would build a quantum computer intentionally for Bitcoins case to frack the 'Shalecoins'. ('Shalecoins', coins with no owner ' https://bitcointalk.org/index.php?topic=5134441.0)

Banks can freeze accounts, rewind, correct it.
But Bitcoin can't.

[thirdprize]

I have been to my local university (Sussex), who are leading the way Quantum computers.  Their Qbit is currently the size of a football with a load of hardware needed to allow it to communicate with the others.  I think they only had about four in total. 

[Wintersoldier]

Quantum computing level now can be a threat, but in the near future for sure. Quantum computing is yes it is powerful but why can't we think it in the good way? I mean quantum computing I think may help bitcoins network to become stronger in security terms.
While quantum computing is getting faster and more powerful I'm sure that the owners of this kind of pc's will not use it in a negative way,  not unless maybe the government ordered it.

Quantum computers use qubits, we think theoretically will be able to do the calculations needed to break the encryption standard in a short amount of time, but this is not a serious threat to bitcoin and other crypto currencies because there is currently no evidence to show that private key bitcoin is in danger, I don't think quantum computers will pose a threat to bitcoin in the near decade.

As far as I know, quantum computer's computation will depend on the application itself, the way how quantum computer computes will be the same way how classical computer does. Since the computation needed isn't for the quantum algorithm, quantum computer processes and computes the problem or task not maximizing its capabilities. In this case, we should not fear that it might decrypt or crack the cryptocurrency.

[ILuckyGuyI]

First of all, quantum computers are not at that level yet. However, there is some rumours that quantum computers can do such big processes very fastly now but I don't think that they are good that much at least for now.