Purely anecdotal.
In India WA does an excellent job of being that social graph. There are segregated groups of family, colleagues, collage friends and what not. Messages, memes, updates are shared on those groups. Lot of commercial transactions also take place.
So Facebook usage has dropped significantly. Of course WA is owned by FB.
We have a similar experience in Latin America.
WhatsApp has become the main method for sharing messages, pictures, video or memes.
WhatsApp groups here are what Google+ Circles attempted to be.
With smaller audiences people are more open to express their real selves in groups.
It's also an integral part of business, like even used for negotiating loans with the bank, getting covid test results or day to day stuff like ordering lunch.