I’ve been mentoring two juniors at work and I prefer zoom actually. It’s a lot easier for me to share my screen with the both of them than it is to all huddle around my desk. If they run into a problem they ping me on slack and we hop on a call together. It’s not any harder than strolling over to my desk.

In Finland there used to be a culture of everyone from high school upwards living in chatrooms or IRC, so it has been extremely natural for people to "idle" on chat channels and interact naturally over those. I would say chat channels feel much more intimate and social environment to me than sitting in an office. Even when we worked in offices we had IRC or Slack or other channels open and interacted over those rather than by actually walking around and talking. It's simply much more effective, asynchronous, and leaves a log of what was said and agreed.