Since quic sessions can be tracked by the connection id rather than the srcip/dstip/sport/dport/ipproto 5-tuple you could switch networks and have your session survive. Not sure if this implementation achieves that or not though.
Since browsers implement QUIC, probably you can run SSH over QUIC on a web browser, making it possible to run ssh client on unconventional platforms that have a browser.
It looks like the multiplexed SSH channels are in a single QUIC stream, so it doesn't help with head-of-line blocking? Honestly not sure what it does from reading the README.