I have a question concerning BroadcastChannel, workers and other communication methods, whose partitioning is being discussed. It's likely that this topic has been brought up before, but I could not find it. If there's a pre-existing discussion, I'd love to catch up and join it; otherwise, I'd love to start it.

Legitimate applications

Legitimate applications could employ unpartitioned communication to the user's benefit.
For example:

• YouTube might wish to pause video playback if the user joins a Zoom/Meet/Teams call.
• Spotify might wish to pause when Calendar speaks out a warning about a meeting starting soon.
• PowerPoint might wish to be remote-controllable by video-conferencing software running on the same machine.

Malicious applications

Malicious applications can rendezvous and communicate using a shared cloud infrastructure.

• REST calls to a shared server.
• PeerConnections
• Any other remote communication method, really.

Difference between legitimate and malicious apps

• Legitimate applications need to work quickly and reliably. "Offshoring" local communication - forcing it to travel over the network - hurts legitimate applications. (It also makes offline operation impossible.)
• Malicious applications are generally more robust to poor reliability, delays, etc.

Question

What is gained by partitioning communication channels, that makes such a trade-off desirable?