Even by reducing a message content to close to 0 bits, I doubt you would get that much gains. Most common messages would probably be things like "lol" or an emoji, which in utf-8 is 24 to 32 bits.
But There'll always be metadata associated with each message: message id, sender, receiver, timestamps, etc. which are unremovable. If those first 3 are typical GUIDs, this is already 3*128 bits. This will put a minimum on the entire message size , and more importantly the processing time to simply route the messages is what is costly in terms of CPU time. Then there's the different receipts mentioned in the article, adding a lot more traffic.
