I think the barbers notch harkens back to the days when barbers were also surgeons. The profile of the toe matches the profile of a scalpel. Looks just like the scalpel blades I used to geld boar pigs and bull calves. The Spanish point mimics the lancet or bleeding point. This may just be a romantic notion (classical allusion) but I kind of like the idea of the continuing blade shapes based on tradition.