Functionally they serve very similar purposes.
The main purpose being destroying thousands of years of written language development.
Emoticons are helpful and can give pointers on the tone of the conversation. See;
You’re such a piece of shit.
You’re such a piece of shit 😛
The latter is friendly banter, the former is an insult, and that’s indicated by the tongue-outy face.
Emojis are a blight upon humanity and probably worse than Stalin. I also hate how some sites automatically turn Emoticons into Emojis.
Why.