Which one is best for learning, an online or an in-person group discussion?

Depends on the individual. I don’t learn much from sitting listening to theory I need to do the thing, preferably several times, in order to begin learning and I need to use that knowledge soon and reasonably frequently or it fades and is lost. But that’s just the way I am. (I have ADHD which plays a role in this.) Not that I can’t join in with theories and discussions arising, far from it, just that it’s playing with concepts. Sitting in a room examining a map and thinking that you know the terrain as a result, from another point of view.

There’s something about being gathered together to learn. Echos of school days perhaps. I would have thought that this part is missing from online learning, and that maybe, for many, the classroom rules learned at school provide a more conducive attitude towards learning, albeit “subconsciously”.