The nice thing about emojis (maybe the only nice thing) is that they are so popular that they force companies and developers to implement proper support for all planes of Unicode, which means that all characters and symbols in those planes that are actually useful are then also supported.
It's not only for emoji, it's also for less common scripts.
I feel just the opposite: emojis are a lot more expressive than text and more universal in language than en-us.
What about winking emojis? I feel there's a lot more ambiguity/nuance with them, which can be a good thing, but can also express something you may or may not intend to.