Ongoing friendship and collaboration is important
Ongoing friendship and collaboration is to be contrasted with one-off replies you might get from people if you post something on the internet, or if you ask someone to take a look at something and they add comments to your google doc or something.
The reason I care about ongoing friendship/collaboration is that if I have to contact a new person for every new topic, that creates too much friction/transaction costs which really drains me.
I think one of the reasons that AI safety is not a community is that it's difficult to find these deep connections.
You can also get much deeper conversations going if the other person already basically understands your personality and understands your assumptions/mindset.