Installation was not a must at that time. 18 months later and the feature has stopped. Recently, Google posted a new support page (first spotted by Android Police) that said, “You can no longer book Uber directly in Google Maps.” The feature had a ride-sharing tab which still exists but will direct you to the Uber App after giving you an estimate once you try use it.
Well, one can say maybe Uber wants its users to use the app more, or the two tech companies have unsolved issues. Either way, the e-taxi app still sources a lot of services from Google Maps that has established itself as the go-to navigation platform.