Using any UTF encoding as fixed-width is almost always a mistake. There's no concept of "characters" in Unicode or the UTF encodings, they use codepoints, and

Using any UTF encoding as fixed-width is almost always a mistake. There's no concept of "characters" in Unicode or the UTF encodings, they use codepoints, and those are only very rarely useful--you cannot treat them as "characters". This is a common misconception with UTF encodings.