They provide a service that lets you summon a car and driver to take you somewhere for money. From the user's point of view, the only structural differences are

They provide a service that lets you summon a car and driver to take you somewhere for money. From the user's point of view, the only structural differences are that you use an app instead of your voice and payment is easier. It's dramatically different on the back end than a traditional taxi company, but the service is the same.