Yes but not everyone owns an Android phone. This can capture those with iPhones who don't want to dish out $400 or whatever for a homepod that doesn't do half the features. For the iPhone user base if they want a smart assistant at home, they'd be choosing between Amazon and Google.
Also I have a personal theory that "routines" are something that's becoming valuable for Google. Essentially configuring a set of actions to one keyword. I can see the potential value in that data, knowing what popular configurations are used, at what times and in what geographic locations.