[KaVir]

Some MUDs use it for page breaks, which would still be useful for a browser client (for example when viewing long lists of information). Some MUDs also use it to wrap text, and may assume a default width of 80 characters if the client doesn't offer an alternative via NAWS. I wouldn't consider it a priority feature, but NAWS could be useful for some MUDs.

I think you'll find MXP is one of those "chicken and egg" features. It has some features I would like to use (such as inline graphics and font tags), but I'm not aware of any generic free clients that support them, and I'm not going to add something I can't test.

For me, the main incentive for changing the font is that it would allow me to use a variable-width font (which looks much nicer than fixed-width), but still switch back to the monospaced font when displaying tables and ASCII maps (as they need to be correctly aligned).