Great ducks to breed, yes, super fun to raise and *some* mothers can be broody but they can be very unreliable as brooders...they like to leave the nest too early and are more likely to do so, the better the quality of the Call. The better the quality for showing, the lesser the quality of the duck's brooding inclinations, generally speaking. They also don't lay all year like many duck breeds, they lay relatively few eggs, so people really want to hatch what they can get from them and not have them only lay as many as they can brood...I personally incubate all my eggs and don't leave it to chance, and I also feel this raises my odds of getting live ducklings because some of the eggs a broody duck may sit on could be infertile. Once she has a clutch and sets, you lessen your chances of getting any more eggs from her that year.
Some people use chickens to incubate them but we don't have or want chickens, so I use machines.