Given Google's orientation towards server-side web applications, it makes sense. On the other hand, the real-time OSs such as QNX have had monotonic clocks available for decades, and they use them for all delay and time interval measurements. (In real-time, you use the monotonic clock for almost everything that matters, and the day clock for logging and display only. You don't want the clock used for delays and time intervals to "smear"; it might have physical effects if it's being used to measure RPM or something and seconds got slightly longer.)

Go is great for server-side web applications. The libraries for that are all there and well debugged. Anything else, not so much.