Facebook has had this for awhile (for chats, at least on web). I rather enjoy it and not really a Millennial, I was born in 77.
I really prefer gifs to all these goofy icons and odd emoji (still use thumbs up etc, just not the poop and other odd ones).
I use Line App for chat with a group for a game I play, and they all love those stickers and emojis. Most of the time I don't even register what it is, and move on - gifs are a bit more eye catching and usually more poignant.
I really wonder how they do financial projections for features like this. How do you even model that? Is it based on retention rates for adding the feature? Certainly users aren't saying "Well twitter has a GIF search now so I can finally join". It just all seems made up. A massive house of cards.
That is not a snarky response.