Now and then, I still set up my terminal or programming editor with a bitmap font. While I am sure you can make an opentype typeface do anything you want with proper hinting, bitmaps still feel more appropriate on the rare occasions where I only have a few (large) pixels available per character. In small sizes, the lack of antialiasing also seems to make the lines darker; again, I’m sure this can be worked around both in OTF and in the OS.
Also, on a much more personal level, I just like the way Fixedsys looks. I wrote far too much QBasic as a kid, and those chunky forms have stuck with me. A modern fixed font like Consolas has good letter shapes and antialiasing, actually scales, and has italics and bold for IDE use — but the symbols are completely anemic in comparison. (Compare the bulgy exclamation point in Fixedsys with the puny colon-like thing in Consolas and you probably see what I mean.)
Of course, fixed-width with a limited number of glyphs that have to be clearly different is a niche usecase — I wouldn’t use it as my menu font. It does stand out, though.