It doesn't seem very practical. For example, you are only ever using an emoji as a punctuation that ends a sentence in the OP, but still using commas which are proper punctuation elsewhere. It also needs to make sense as a spoken language as well, so emojis would not translate well in an attempt to read a sentence aloud that has used emojis in place of actual punctuation. Then there is the fact that besides typing digitally, we also need to be able to physically write, or at least, it is a useful skill to have that I don't imagine will go away anytime soon. Drawing emojis as punctuation would only make writing more tedious than it needs to be.
If i remember right, a lot of early forms of written languages started out as sort of illustrative drawings similar to Egyptian hieroglyphs (this is definitely true of Kanji, at least). Those illustrations over years were simplified more and more until they were no longer full drawings, and instead merely lines that sort of abstractly represent the original idea of the drawing. As long as there is still a need or desire to physically write, I can only imagine something similar happening over centuries because we prioritize simplifying for convenience if possible.
Plus if inserting emojis as punctuation was actually attempted in formal writing we would have to completely overhaul our language and redefine the rules of it.