> There are only three places where I hold letter-spacing of any kind to be acceptable:

Three more that I'm aware of:

4. For emphasis in Fraktur text [0].

5. In very small amounts (< 2%) to improve paragraph breaking [1 §7.2].

6. For very large signs where readability is more important than aesthetics [2, 3].

These are all rather special cases though, so I still agree with your general point.

[0]: https://unifraktur.sourceforge.net/en/letterspacing.html

[1]: https://tug.org/TUGboat/tb21-4/tb69thanh.pdf#page=95

[2]: https://mutcd.fhwa.dot.gov/SHSe/Alphabets.pdf#%5B%7B%22num%2...

[3]: https://mutcd.fhwa.dot.gov/SHSe/shs_2004_2012_sup.pdf#SHS%20...