[mostlylurks]

> Text is universally compatible, whereas emoji introduce compatibility and versioning issues across browsers and operating systems.

To be specific, they introduce a lot more of such issues, but such issues were already there with plain text as well. Fonts that don't support some characters, fonts where some characters are displayed incorrectly (the whole CJK unification fiasco), fonts where some characters are not distinguished (I've run into the is-this-an-I-or-an-l issue quite a few times, personally).