Emoticons are not the same as emojis. For one they allow for more expression or personal style by having different variants, e.g. :-) vs :) or for absolute maniacs: (:
They are also not limited to what some consortium and a couple of megacorporations think you should be able to express.
I think there's a difference. The code point will always mean "eggplant", it just happens that the concept can be interpreted in different ways according to context—just like the word itself. But ":-)" can only ever mean "colon minus rparens" before further interpretation.
What’s it called is syntax, what it’s means is always context dependent. That’s why we invented formal notation, so that we can have context free interpretation (it’s bundled with its semantic so you don’t need to apply some context to it)