I turned it off because the "default" use case seemed rather to be to boost their engagement because someone you know socially would upload a picture of somethi

I turned it off because the "default" use case seemed rather to be to boost their engagement because someone you know socially would upload a picture of something they did that happened to have you in it. That would lead to you being tagged and getting notified, presumably to talk about how much fun you all had or whatever it was. Unfortunately it's pretty useless to ask people to not upload pictures that you're present in, and FB used notifications essentially just to get you to open the app and re-engage. I turned off everything that generated useless notifications for a while, then I finally turned off notifications completely.