Where is the users carrot?
Unless I'm reading it wrong, I don't see any mention of what benefit this offers the end users?
It's a standard that only seems to run on one platform (Android).
It will cost users money to use, i.e. the same model as SMS/MMS, so needs funding somehow.
It doesn't seem to provide any tangible benefit over current SMS, which works everywhere on all phones, universally.
It seems to be worse than existing messaging apps. as it removes a layer of privacy.