They also do do normal diplomacy to some degree too, which is basically the obvious part of advancing one's interests - but a lot of stuff is definitely going to be easier to work out face to face.
There is also the problem of technical difficulties.
Setting up secure, verifiable communication channel that is available regardless of disaster or other difficulties would be hard.
I understand most people are used to Zoom and equivalents, but observing is different from making decisions at the highest level. I also think that some of the communication is of the kind that you would want to be sure cannot be recorded.
