Hopefully it will be the default once implemented. Everyone will benefit from compact protocol in the long run. Should have been done from the very beginning.
Is there going to be a way to have very simple clients, perhaps with a helper in the server side?
It'd be nice to bring matrix to microcontrollers and "retro" computer platforms.
the API already is super simple, and low bandwidth could already work on retro machines (I had 6809 in mind when experimenting with it). The problem is e2ee, but we have the Pantalaimon e2ee proxy to convert unencrypted Matrix traffic into E2EE traffic for precisely this sort of thing :)
It might also get changed as part of Sliding Sync refinement.