Yep, if you go for that seperate step in handgun reloading of applying crimp as a seperate step, then the 4th stage comes in handy. Lee is now selling their delux handgun die set as a set of 4 dies including the factory crimp die.
Or you could go the other way and install a universial decapper, or set up one stage as seperate powder charging, etc.
I've used the old 3 station and at least at the moment don't plan to change. but the 4 station does appear to be the future of things to come as that is all they offer in the classic cast turrent.