The documentation isn’t great, I’m learning Core Data at the moment and it’s unclear and riddled with mistakes. Google’s must be terrible if it’s worse.
Support for major Google features and initiatives often sucks—Material generally, and as of a couple years ago their Maps library was worse than the JS version in some important ways, such that you'd end up calling out to javascript if you needed something as little-used as, say, address components (rather than one big address string). Yes, seriously. This is a pattern for them. I don't get it, but that's the way it is. Android's not built on a great foundation, and sees a surprising amount of neglect and half-assery in its ongoing development.