Its the first thing I do toa motorbike if braided hoses are not already fitted. If the car is a few years old, and it sill has its original brake hoses, it would be a worthwhile mod. The change isn't goind to be staggering, but it should give a more solid brake response, because your energy of pressing the pedal and moving the fluid goes only to pushing the pads against the disk, and not into expanding tired rubber hose. That said, on servo assisted brakes you loose a lot of that feel anyway.
So yes, its worth doing but don't expect a massive difference,