I would argue that there is much to miss on by wasting time looking up Jenny from primary school when you have your kids, friends and family who you meet day to day.
There is actually an option to run into mental health issues that we know social media is causing.
Yes, absolutely. The paths our lives take can lead us to have more in common with someone we knew in the past then when we first knew them. And there's a lot of value in having a history with someone, compared to getting to know someone new from scratch. Maintaining loose contact takes virtually no effort but can lead to meaningful interactions down the road.
However most of my "Facebook friends" were shallow faint contacts, where paths may have been close for a while but went apart as each went on with their lives. No more scrolling through which bar they visited, how their kids are doing, or which TV show they were watching didn't take anything from my life, while it encouraged me to reach out more actively to people I really care about, as I didn't "rely" on passive information anymore, assuming to hear about "relevant" events, but became interested in them and shared things which wouldn't make "public" social media.
I would not feel comfortable, to say the least, I would feel creeped out. I would start thinking what kind of MLM he joined or if he looks to borrow money as last resort as no one closer would lend him any.
If that would be my close friend that would be OK.
If I run today into someone from primary school we probably will connect over that.
If that someone will start talking how he have seen photos of my trips or my life events or how he totally loves band I added to my profile half a year ago - without ever sending me even happy new years message - I will be creeped out - and totally not “aw cool you follow my posts”.