It includes this exhortation: "If you want to keep sharing your local knowledge with your neighbours, we encourage you to become a Google Maps Local Guide."
It really looked like they made the app and just sat tight and kept their fingers crossed. There were no promotions, no cross app integrations, no call for partnerships (for example with gated community), etc.
Google Product Management is something I always wonder about - I have experience working with the ones in Microsoft and Amazon, and I suspect PM culture in these places are vastly different than in Google.