“He has completed the task.”
versus
“He pulled it off.”
Their meanings are the same but their both have different subtext.
Emojis are simply additional levers for subtext. It’s like using a red hot colors versus cool colors for a poster — the text might be the same but the colors provide an additional way to signal subtext.
The more options, the better.
You don’t just put the same laugh emoji every time it’s funny…
we make up words all the time, and they are in fact not all "agreed upon" because language changes, like how awesome used to mean "inspiring awe" and "literally" now means "figuratively" and how "google" and "tweet" are words.
emoji change meaning quicker than words, yes, but that's because the were born online and because they are easier to add semantic meaning to. they're pretty neat, to be honest.
even in a corporate setting we use emoji all the time to +1 things, to confirm something, or on video calls to give kudos, and more.