Yes I know about that, but that kind of defeats the purpose, right? If I have to type 'pizza' to get a symbol for pizza, I can just use the word itself. Or do people use them to communicate with illiterates or people who speak a different language? ;-)
It used to be that emoji were just to express some feeling that would otherwise take a lot of words, or to disambiguate statements that could mean different things in different context (sarcasm/irony, jokes, etc). Emoji are are very useful for that. Like the parent I replied to I don't understand the use case for almost all of the other emoji.
An emoji isn't really a shorthand for a word or phrase, using an emoji has its own unique meaning. Responding to something with (heart-eyes) is interpreted differently to anything verbal, like "I love that." In the same way, you can't substitute facial expressions and vocal tones with more words. It used to be that you'd have 10-30 emoticons directly representing facial expressions, the only thing that's changed is that now people pair multiple emojis to create emoji-phrases that can represent more elaborate gestures and actions. A lot of the weirder "why is that a thing" emojis are there to enable that. Stuff like rolling-eyes + gun-to-head, ️blank-stare + man-fleeing, raised-hand + crossed-arms (time out), etc. If your SO tells you they're picking up pizza on the way home, pizza + heart-eyes, pizza + orgasm, partners + pizza = love, etc have different meanings and vibes to stating "I love pizza."
It's interesting because it's no longer just filling a gap in textual communication, but using textual communication to express a thought or joke that you can't really express with the same interpretation in any other conversational medium. Responding to "and Dave will be there" with blank-stare + man-fleeing expresses something you could only really express otherwise by drawing a comic strip on the spot and handing it to someone.
It used to be that emoji were just to express some feeling that would otherwise take a lot of words, or to disambiguate statements that could mean different things in different context (sarcasm/irony, jokes, etc). Emoji are are very useful for that. Like the parent I replied to I don't understand the use case for almost all of the other emoji.