It's a "full hybrid:" in that it can run on its electric motor alone for short distances at low speeds.
The Prius was designed, from the outset, to be a gasoline/electric hybrid vehicle. That enabled designers to create the body around the hybrid system rather than cramming batteries and an electric motor into a body designed to house just a gas tank and an engine. For that reason, the Prius has plenty of usable storage space.
With its unique body design, it's also instantly recognizable as a high-tech hybrid car, which only increases its appeal.