IIRC A gyro is quicker and more precise than a digital compass. Think about it as... a compass is good for orientation, a gyro is good for recording motion (especially the yaw component). A compass will never be as precise as a gyro to tell you how quickly you are turning (ever see those iPhone augmented reality apps ? You moooove theee deviiice sloooowly or it get's jumpy real quick). At the same time the gyro will not be able to tell you which way is North without constant (re)calibration, so they are not drop-in replacements. AFAIK no game controller has gyro(s) *instead* of accelerometer(s), they have gyros *in addition* to accelerometer(s).