Kinda depends on what you want to use it for. If you want to simulate a physical system then you need at least as many qubits as the system has (and an understa

Kinda depends on what you want to use it for. If you want to simulate a physical system then you need at least as many qubits as the system has (and an understanding that such a simulation will have terrible noise). If you want to do something “useful” like run Shor’s algorithm to factor large encryption keys then it would take millions of qubits and quantum error correction. To me the significance of this kind of increase in number of qubits is that many detractors of quantum computing had argued we’d never even reach this point, so I am slightly more optimistic that we’ll eventually reach the scale required for reliable abstract computations.