For me it's important that the butt end of the edge not run right into the ricasso, and that's where I like the choil to work. This makes it possible to sharpen right to the end of the blade without interference from the ricasso.

As a "sharpening notch" the choil doesn't have to be very big. But a notch like that one on this knife, that's too small for a finger and doesn't terminate the edge seems useless. Maybe for a firesteel striker, but that's probably not a designed feature.

In general, a ricasso can help when sharpening, if one uses a jig or table system (like Lansky and EdgePro, respectively). It provides a flat reference plane for clamping or establishing a fixed angle.

Bear