But the currently encoded sub/supersripts counter that general view?

> agree as there is tons of useful formatting that one could want

So? Should we stop adding emojis just because the potential is infinite?

> And if we do Latin alphabet, then should we also do Greek? Cyrillic? Arabic?

Add a combining prefix/suffix and you wouldn't need to do encode every single char from those alphabets. But also the general answer exists: whatever is commonly useful.