>but I still haven't found a way for it to add value to my life.
I think one of the most useful cases of these sites is looking for conversations by people on a subject you are interested in but don't have a lot of real life connection to. For example I was really interested in China studies, so I found a list of Sinologists. Just reading what they write, what sources they recommend and "listening in" on it is a very good way to get exposed to all kinds of stuff you wouldn't even know to search for.
And there's lots of fields like this. Maybe you are interested in abstract expressionist art. What's the chances you know a lot of scholars unless you are one? These networks of really interesting people is I think where the value is in platforms like this.