"The major issue I cover, though, is the inherent flaw on page one of Satoshi’s paper. That elegant if pesky line about “computationally impractical to reverse” transactions. You see, the crypto behind cryptocurrency is actually public key. We are likely less than three years away from this being completely hackable by a quantum computer."
quote from the article Blockchain has a huge security flaw - can it be fixed?

The point is "public keys are hackable".
The other point is that Quantum Computing can hack algorithms.
QD Physical Keys do not use algorithms and are not hackable.