No, by "not a good" he probably means that it's not well suited for low battery consumption expected from a mobile device.
Don't push your words on other people :(
The battery argument is just misinformed. The real reason Google dropped XMPP was not a technical one. Yes, Google claimed it was not "cloud ready" at that GoogleIO. The same one where they announced Google Cloud Messaging, based on, wait for it, XMPP.
IIRC WeChat started from the ground up with a custom protocol designed for compatibility/efficiency with low bandwidth mobile networks for maximum reach, IMHO a great example of thinking outside the box of "let's use XMPP since it works".
Just curious, who else is using that protocol?
Don't think anyone is, I thought there was a hacker news story on it but I could not find it with search, sorry.