Which is why we have standards for conveying any conceivable image in raster or vector form.
Instead of selecting an easily compressible format for embedding any small image inline with text, we're trying to force a writing system into a kind of general-purpose icon library.
We could've had a world where carriers and phone manufacturers each had their own "common" images easily entered from some list like now, but still allowing cross-platform transmission without information loss, and enabling users to easily add their own custom images.
Now Unicode is stuck trying to define a finite set of popular words which every platform renders slightly differently, and will always leave something out or offend someone.