It's one of those things that may be technically possible but that doesn't matter unless a large enough percentage of other people are doing it too. Now that everything is geared to be realtime, anything most people will want to do on a computer will have those kind of traffic patterns. Even our popular application platforms are set up to encourage this pattern. Electron being a browser engine is geared around making network connections first and foremost.

Maybe I misunderstood your point. Why do you need everybody to be doing it?

Concrete example: if my friends only use Discord and I want to talk to my friends, I have to use Discord whether or not I think it's bad for me.

That's true of Discord, but it's not really true of deploying your own CA certs.