I think there is a difference: with emojis, only the sender knows the precise meaning. Words have agreed on definitions.
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.