The idea that every application should ship their own glyphs because some proprietary systems do not have normal fonts, is not great. Fix the terminal instead.

Also, if you want advanced GUI with icons, maybe you should just write a GUI app.

As for shipping custom icons, this is not very bright idea as well. If you switch between several applications on one terminal, then one application can redefine glyphs from another application. Also, when the application terminates, nobody cleans up its glyphs. Also, this increases attack surface because font standards are pretty complicated and one will be able to attack the system by just providing a glyph. We already have programs that can break the terminal, which should never happen.

Also, as for icons, I find emoji characters too distracting (and too large). They stand out too much and take away user's attention, breaking any visual hierarchy. The icons in terminal should be monochrome, and with thin lines, so that they do not distract you from the text and its structure.