Although this appears to be a great achievement, pending independent peer-review of course...

The fact is that that it is still a big unanswered question in physics as to how the number of qubits with superposition of their quantum states will scale in terms of time and energy. Many physicists think that this might scale scale exponentially.

So yes, we can expect to make quantum computers with a several (maybe even a few dozen) qubits with superposition of their quantum states; but if we need to double the time and energy as we add more qubits, it becomes impractical. Even if one find 10x or 100x improvements in obtaining superposition, if one does this with the large number of qubits needs to break classical public key crypto, such as RSA (via factoring), or DH/ECDH & DSA/ECDSA (via discrete log), it may take more time than the projected heat death of the universe and/or more energy than in the universe, especially with large key sizes.

Note that quantum computer systems such as those from D-Wave now have 2000 qubits, but these function without quantum superposition of their qubits, and hence cannot be used to break public key crypto. Mind you, even without superposition, D-Wave systems appear be to many times more efficient in computing some things compared to classical computers, such as for some types of simulations, so they are still useful in there own right.

Physicist should would find out how qubits scale, long before anyone is able to build one capable of breaking public key crypto. By then, there are a number of usable but less efficient (bigger & slower) quantum resistant public key alternatives which we can switch to, such as lattice based crypto, long before there is any quantum computer risk to Internet security.

In terms of science fiction risks to crypto, I am much more concerned about super-intelligent AI (or really clever human mathematicians) figuring out some shortcut to undermine trapdoor functions which public key crypto is based on, than I am with quantum computers.

And currently, the biggest risk to worry about are the countless security flaws and backdoors in modern hardware and software, such as Intel VPro/AMT, and organizations such as the NSA undermining crypto standards and protocols.