I certainly do use them all. Mind you, most of my feeder and quiver rods predate carp commercials, and were, and are, used for species much less likely to hang themselves on the bite or for methods other than self-hooking method-types. Better rods often came with 3 tips, and these often all blended into the action surprisingly well. Some manufacturers' tips - Daiwa and Shimano, for instance, were common to different versions of a model, or even different series of rods, and having a wide range of tips in your bag allowed you choose something just right for the flow, tow or species you were after. Even in a given "test curve" , like 1.5 or 2 oz, there are important differences in the way carbon and fibreglass tips behave, and between fast and slow taper tips. The carrier section plus tip arrangement also allowed you to to bring in non-standard bite indicators like springtips and swingtips or tips of your own making. I have dozens of tips that will fit my Shimano and Daiwa rods, but with the rods that come with tips integral to the whole section, I only have a choice of two, eg the Preston Carbonactive Quiver. Some may have more, of course. You could argue these spliced-in tips give a better action, but I've never noticed any practical difference, and you certainly notice a difference if you break a built-in tip, as you'll be paying for the whole section rather than a new tip. I'm not really into making up rods - barbel rods excepted - at home, and in many cases, I want to see the water and assess what's needed before I chose a tip, and even then the first one I try might not be right.
I have the impression that before the heavy, self-hooking feeder became widely popular, along with variations on bolt-rigs, anglers treated quiver tips a bit like floats - and even though I live near some big tackle shops, I wouldn't be able to find equivalents for half the wagglers in my float boxes, with all their variations in bodies, thicknesses, lengths and inserts.
