This is about quantum messaging not quantum computers. They don't have the same requirements.

However its pretty useless. QKD, does basically the same thing as the diffie-helman protocol, except with less math assumptions. Like diffie-helman it protects against passive evesdroppers but not active man in the middle. Any real system is going to have to use traditional crypto for active MITM protection, and if you are already using traditional crypto, might as well use it for the whole thing.

In essence this is a cool science experiment but doesn't really offer meaningful improvements over traditional crypto methods.