Facebook's biggest strength for me was in navigating the first couple months of a new acquaintance becoming a friend. Sharing numbers and managing all that is cumbersome. Adding someone on Facebook was easy and if the relationship didn't pan out, it was painless to keep the contact or purge them later. To me and a lot of people I know, texting is an intimate thing whereas Facebook was not.

Note, I left Facebook some year ago, and my mental health is better for it.