Wow! Thanks for posting a link to that article! There is excellent coverage of different methods, pros and cons. It’s good they covered file maintenance, especially file cards.
One useful method not covered: “Draw filing” is a method of using a file to sharpen by running the file along the edge of a tool without much or any forward push. The angle needs to be found where the file “bites” into the metal. A very sharp edge can be put on machetes, shovels, etc.
So far, I’ve not used carbide sharpeners, opting for fine or coarse files, if a lot of metal needs removal, or many different stones, from super coarse, to 8,000 grit or Arkansas Surgical Black stones, for straight razors, scalpels and grafting knives. (The scalpels get used when I graft seedling tomatoes under magnification.) Both files and carbide cutters need additional finishing with stones to remove burrs and ragged edges.
When I worked at a vineyard, the work crew which pruned countless grape vines used those little pocket stones, which looked like the Felco 903 diamond stones. They would prune all day, so touched up the blades many times throughout the day.