I imagine they'll try to get new users to sign up for a month of Premier to try Waymo early once it becomes available in their city. Basically juice a few thousand early adopters for 30 bucks each, which also lets them judge demand and gives them some extra revenue to build out their vehicle/parking network before the full launch.

Or it for frequent travellers - if they did smaller "beta" testing in a ton of new cities at once it could be great to suddenly have access to a semi exclusive fleet of Waymos

Pay $30 to be a beta tester for self driving cars in a new city. I wouldn’t sign up for that.