Hi Reid,
I noticed that you only focused on "chopping." Out of curiosity, what about slicing?
The blades are probably made for agriculture, but as someone who had one custom made many years ago by Walter Sorrells, I like to keep the fantasy a little.
The blades on the antiques that I have seen are always kata-kiriha in cross section, and as a carpenter, I can fully see this blade shape being used to allow the user to trim whatever they are trimming as close and flat to the surface they are removing it from, however, this would also possibly aid in slipping through joints.
We see the Kata-kiriha cross section on hocho, though, so I wonder what exactly the cross section was meant for.
Maybe they were the knives of head butchers or head gardners?