The shift lever is just a big electronic switch. You can manually shift your transmission by tilting the lever left to right. The pushbutton shifters have the steering wheel paddle shifters to manual change gears, but both are just electronic switches. U.S. doesn't offer the mild hybrid car, only HEV and PHEV. The mild hybrid is a completely different vehicle. It doesn't have a traction motor, only a starter generator that runs on 48 volts, rather than the 200+ volt systems on the PHEV and HEV. The mild hybrid starter generator functions mainly as a start/stop motor and provides a small amount of assistance to the gas motor, usually when moving from a stop. It also works as a generator to recharge the 48 volt system and to maintain the 12 volt system. Your car has a dual clutch transmission, basically an an electronically shifted manual transmission. The HEV's have two motors, the starter generator and a much more powerful electric motor. It has an electronically controlled 6 speed transmission with the larger traction motor mounted between the engine and transmission. It almost always runs to power the car, sometimes by itself, other times to assist the gas engine. As to why some come with buttons and others shift levers, I have no idea.