And of course there the creep factor.
I'm having a hard time determining if Facebook is just terrible, low value, and creepy, or I'm just cynical about Facebook. Probably both.
They are for things like for a bowling team in a league or a user group or other ad-hoc group of people who want to communicate with each other - co-ordinate dates and times, send out last-minute updates. The hope, as I understand it, is that it will reduce confusion/anxiety/overcommunication over who hasn't yet read something ("Did Mike read the update that mentioned he is supposed to bring the projector? Should I send him a direct message/phone him?").
Pages already have Insights which gives them aggregate-only demographic data about the audience who has interacted with a particular post ("52/48% female/male, 80% US, ...").
(A Facebook engineer, but not involved in this feature.)
Zero friction, sure. I'd call it zero consent. Most Internet lay users don't have the mental capacity to understand the legalease of a TOS, so to me saying they agreed to it is thin moral ice to stand on.