Back before there was OpenType, and before Windows had Unicode support, if someone wanted to type text in Georgian or Greek or Armenian, they had to use a special font that printed the glyphs for the characters desired for the character codes within ASCII or at least ISO 8859-1.
Although that's a highly deprecated practice, it is awkward to change keyboards in Windows. Furthermore, I'm not aware of a chess diagram keyboard, for example.
It has occured to me, therefore, that some people might find it very useful to be able to type special characters by the following process:
Have 7-bit or 8-bit fonts which replace ordinary characters by characters in the more distant parts of Unicode, but which also associate with each character the value of the Unicode code for the character the image of which is being printed...
and provide in word processors, including simple editors with text styles (i.e. WordPad and the like) a "Paste as Unicode" function. (Of course, that pastes text in a default font, one would then have to change it to the Unicode font you want.)