One problem with grapheme clusters as length is that you can't do math with it. In other words, string A (of length 1) concatenated with string B (of length 1) might result in string C that also has length 1. Meanwhile, concatenating them in the reverse order might make a string D with length 2.
This won't matter for most applications but it's something you may easily overlook when assuming grapheme clusters are enough for everything.
This won't matter for most applications but it's something you may easily overlook when assuming grapheme clusters are enough for everything.