Sorry, the question was actually rhetorical: those glyphs are in no way obscure, they're super common. A text isn't monospaced or not, a text is just a text, monospaced is a property of a typeface that can be used to render a text, it's adjacent to other properties of typefaces like serif or sans-serif. When you dismiss stuff like ü or ø or ß or etc. as "obscure" (and, transitively, irrelevant) it comes across as ignorance.