Gas turbines operate efficiently at constant output, which a hybrid-drive system with storage can manage. They only need to kick out enough power, on average, to keep the storage system fully charged. Batteries and eletric motors can handle both high-demand accelleration, and regenerative braking. Since the turbines are running at a very constant range, and can be rated to average out power load inclusive of idle times, they can be designed for optimum efficiency within that range. Or that's the theory.

There've been other gas-turbine automobiles, including some prototypes built in the 1960s. A friend of mine test drove one, claimed it could lay a patch (spin the tires) at highway speeds. Though my understanding is that in direct-drive applications (such as that), turbine lag is an issue.

The exhaust also runs quite hot, and turbines typically emit a lot of NOx (nitrous oxides), what you get when you run atmospheric nitrogen through a high-temperature field.

Much anecdata here, apply salt liberally.