"it's backed by Google" is the reason I avoided Go for years and is still the only reason I'm nervous using it.
Look at android, it's a closed project that the occasionally release some source code for. If google decided to drop android then it's a critical blow because there isn't much of a community around it.
It's "open", but it would almost certainly collapse entirely if Google decided to drop support for it. (There's no sign that they'll do that, but it's not a risk you take with a language like C.)