Judging from this write, the whole concept of the Quantum computers and computing is quite interesting and caught my attention, but I've got a little concern and a question to ask.

looking at the possibility of a certain billion Qubits being able to crack a Bitcoin private key, don't you think such tool will be very dangerous in the wrong hands, and could also be disastrous(I mean to those in possession of large amount of Bitcoins) if not properly handed??