It turns out the Lyft model, where the driver doesn't know whether or not the rider tipped, is better for the rider. The rider doesn't have to carry cash in order to avoid getting extorted for a 5-star rating.
Tipping culture in restaurants is subsidizing substandard wages for servers. Tipping culture for taxis and the gypsy cab apps (Uber, Didi, Lyft, etc) doesn't have to take hold. Maybe now that the option is in-app, riders will eventually stop using it.
I hope, at least, that the tipping option is confined to U.S. rides. The rest of the world doesn't need to get infected with it.