Maybe it's just because I'm a dirty heathen who does it wrong*, but I don't bother trying to sharpen the transition area. Instead, I treat the tip and belly as distinct edges to sharpen. Which makes the tanto a far more utilitarian blade for me, because when I use and dull the tip doing mundane things, I can easily touch it up with a strop or stone.
I find it one sharpens up to the transition on both sides, it results in a nice pointy transition that is sharp and also has a slight hook to it that allows for easy pull cuts.
Count me as one of the people that views the American Tanto as a useful design. But I also find wharncliffes useful and a lot of folks don't.
*Unpossible, since we know I never do anything wrong.
All these things...
“There is no growth in the comfort zone.”--Jocko Willink "You can never have too many knives." --Joe Ambercrombie