Absolutely. Dropping GCM and rolling their own for that is great.

But SMS still is the more reliable protocol. When I'm in a subway without stable data, and I tell my girlfriend I have an expectation for reliability of delivery that is shaped by SMS. So does she.

Roaming data is disabled by default on Android for good reasons, I pay insane amounts for it on my otherwise fantastically cheap data plan. So I am in Paris and all of a sudden her messages don't get through.

If there is an intelligent fall back to unencrypted SMS this could be a boon though. The risk of undelivered messages very strongly outweighs the risk of these messages being read in these use cases, so if SMS can not be made secure and usable, unencrypted fall back is absolutely fine.

I'm not sure that it makes sense to optimize a service to be as effective as possible under roaming situations. They were obviously spending a lot of engineering resources dealing with SMS edge cases.

They even justified focusing on their own open protocol over data as being useable by more people in the world. Any time you make a change, your going to impact usability for some people. But it sounds to me that they're going in the direction that increases global adoption and mind-share of encrypted communication. It's way too early, and adoption is way too low to sacrifice broad adoption (by not focusing enough) in favor of supporting current edge use cases.

Wifi?