Who I have the same questioned this solution

I have this problem too! The first thread I found on the issue was here, but has been locked for some reason:
How do I disable auto emojis when I text using Verizon Messages ?

I love the app other than this one issue. I know that other people can't see it, but it makes things look terrible on my phone, and it doesn't make sense to show me something that no one else can see!

As noted in the thread I linked, this is NOT the smart emojis feature, which highlights certain words to turn them into actual emojis. This is a dumb "feature" where typing smileys (such as 🙂 or 😛 ) gets them replaced only on your personal phone. Yes, adding a space after the colon "fixes" the issue, but it's not much of a fix when it's super inconvenient, and should be turned on or off as an actual option in settings.