It's an industry standard, but if Apple doesn't implement it in iOS then it's only useable from one Android device to another.
That effectively makes it into crappy iMessage for Android. Only works within one OS ecosystem, but it's unencrypted, managed by your carrier, and limited to the one cellular device itself instead of also working directly on your wifi-connected tablet and computer.
It would be nice of Apple to support this if it's an improvement over SMS/MMS, but Apple drags their feet on supporting any sort of standards that they didn't create. And even some that they did (pour one out for OpenCL).