They required every graphics stack to add support for color fonts. And because new emoji compositions are invented every year, it's common to see uncomposed glitches like <facepalming woman><male gender marker> or <thumbs up><white skin color marker> on all sorts of semi-smart devices.
In my opinion Unicode went from a slow-moving standard that carefully absorbed the world's languages, to a pop culture product that serves to make old software obsolete even faster.
