Missing discussion in README of why this instead of mosh

[dklempner]

The readme is missing any discussion of why someone would use this instead of mosh.

In general, mosh is a story for something very close to "ssh over quic" for most users -- with the major caveat that quic didn't exist when mosh was originally written, so mosh uses its own UDP protocol.

My impression is that this does have a few usecases, such as if there's a firewall that allows QUIC but not generic UDP, but it's probably worth calling those out.