I use a round beech mallet for carving, a small one on small Henry Taylor chisels. I don't do much these days. You don't have to think about the orientation of the head, one fewer way to mess up. Plus comfort, your wrist never needs to twist just flex naturally. Plus they curve a bit top to bottom as well as round so you don't need to be precise that way either, it still strikes the chisel with a straight force. Plus it evens the wear on the head, not that it would matter for what I do.
The big plus is that it is such a lovely thing, a pleasure to pick up, hold and use.