From Angus Row Boats: https://angusrowboats.com/blogs/news/everything-you-need-to-know-about-sculling-oars

“The two basic blade shapes for sculling oars are Macon and Hatchet. Macons are the more traditionally shaped symmetrical blades and hatchets are asymmetrical. While hatchets are reputed to be fractionally faster (almost immeasurably), Macons offer two distinct advantages for recreational rowing. Being symmetrical, the oars can be used on either side of the boat – particularly beneficial for a spare oar. More importantly, if you decide not to feather due to injury or inexperience Macons are much better at being used without feathering. Hatchets extend further down and are more prone to catching the water.”

I have used the Macon oar often and found it wonderful. Other rowers thought I was nuts. The hatchet oar, of course, reigns supreme in competition rowing, but paddling is an art and a greater understanding of why this is can be found in the original oars used by the Inuit: