Can you seriously not distinguish between the tiny selection and low res quality of text faces, and the wide variety of highly specific and detailed set of reactions now available to us? There's only so much you can do with text before you have to be extremely creative (a level of effort excessive for quick casual conversations) or rely on the other party being familiar with your specific vocabulary of text-faces.
Then give us a single example! So many replies _and not a single example of where words or ascii fail to impart what only an emoji can_. You can say "they're obviously better" until you're blue in the face, but it's all hot air until you prove it.
Obviously words can (almost certainly) impart what an emoji can - but one small image versus maybe 100 words? That's before you start combining them and the expanded meaning you can get from that.
You might as well say "give me an example of where Proper English fails to import what only slang can" - you're missing the point.
I have the choice of either adjusting my writing style to new people, which I’d rather not, or use either text or picture emoji to convey the tone that makes my writing clearer to people who can’t infer it. I find that image-based emoji are much more specific in the mood they convey, and provide more range — and there is a definite difference in how clearly I come across.