What my setup does is allow me to split nearly every gear, using the FD. For times like when the headwind gets just a bit stronger, I can go down a half-step, rather than 1 full gear. Extremely good for flat-land riding. Slight inclines that don't require a full step change, also. And, by 'extreme gears', I mean like a 53-11 combo; unless you are in the TdF, you rarely see anybody use this combo, so why carry them around if you don't need them? If you never need gearing above a certain lever (measured in gear-inches), you will be better off with a cassette that doesn't have them.