I used to kind of think this, but for me reaching out slack has turned into something I really appreciate. I can asynchronously ask someone to get in touch with me. they do when they are ready. i dont interrupt them. i can continue doing other things. there is no set meeting time, we can just have a little chat with zero effort, say goodbye and go back to work.

at the end of the day after doing this I do feel more tired, but I get plenty of self-scheduled productive little discussions.

I've mentored someone remotely and it seems to have gone pretty well. Doesn't hurt that they person is very good. And, yes, chat is invaluable.

I still feel you're losing something without in-person (including social) interaction. I know for me personally, I would say I have much weaker connections to many people I've never met in person. That said, there are a bunch of other factors involved with building new connections as well that aren't purely about being virtual.