The allure is fairly self-evident: you can rent a car from the same app you'd use to hail a ride or grab a bike, and you don't have to stress about visiting a rental counter or driving limits.

For Lyft, this is part of both a larger effort to cover many forms of transportation and shore up its bottom line. It has long wanted to be your go-to provider no matter how you want to ride. And when Lyft expects to see its steepest losses this year, it needs options like car rentals to boost revenue and (eventually) turn a profit.