There are few other implementations of the same idea out there, too. Here's another one: https://github.com/qntm/base65536 ; since it uses a power-of-two sized alphabet, it avoids some of the work mine has to do around partial output bytes. That link also links to some other ideas & implementations
The exact metric I cared about at the time was compressing for screen-space, not for actual byte-for-byte space. I wrote it after spending some time in a situation where doing a proper scp was just a PITA, unfortunately, but copy/pasting into a terminal is almost always a thing that works. But I was also dealing with screen/tmux, which makes scrolling difficult, so I wanted the output to fit in a screen. From that, you can implement a very poor man's scp with tar -cz FILES | base64 ; the base-unicode bit replaces the base64.
Mine doesn't use Huffman coding as it wants to stream data / it leans on gzip for doing that.
Which I discovered because, for Hatetris, he wrote a nice twitter-oriented compact binary-to-text encoding, base65536[2].
It's actually pretty useful for compressing data in Unicode-aware environments, like Twitter. Which makes me wonder if Unicode support is universal enough now that an encoding like this could replace MIME/base64 in email.