That exact symbol, thumbing up someone's text was created so Facebook could track concrete USER ENGAGEMENT in 2010, so they could specifically track what it's users engaged with the most. A quantifiable metric.
that's it. all the emojis and new emojis and all that shyt, is just to keep it's users engaged. if you are having so much fun using all the emoji's and memes, and the visceral dopamine drip of the PING text alert, and the BRIGHT RED messages alert you won't notice you are fukking fixated on your phone for hours at a time.
that's all this is about.