I'm imagining coding with some random "i" being a different completely undistinguishable character from the English "i". Or people writing your name and not matching in their DB because their local "i" is not your "i".
It's a potential issue already depending on your script, and CJK also has this funny full English alphabet but all in double-width characters that makes it PITA for people who can't distinguish the two. But having it on a character as common as "i" would feel specially hellish to me.
Cyrillic 'e' is isolated in that you switch script when writing it. I'd compare it to the greek X.
Turkish isn't on a fully separate script, most letters are standard ascii and only a few are special (it's closer to French or German with the accentuated characters), so you don't have the explicit switch, it's always mixed.
It's a potential issue already depending on your script, and CJK also has this funny full English alphabet but all in double-width characters that makes it PITA for people who can't distinguish the two. But having it on a character as common as "i" would feel specially hellish to me.