Pull through type sharpeners are the enemy of all knives and if you believe them to be a usefully item then you edge-u-cation is in its primal stages. Regardless of the abrasive used in these type sharpeners you will always end up with a heavy burr formation to one side of the blade due to the orientation of the abrasive rods/plates/scrappers in the device.
The simple fact is they are awful for sharpening a edge and should be well known as such by knife enthusiasts that are part of a internet forum devoted to knives.
Frankly I find this absolutely wrong. If you cannot figure out how to use a pull through carbide sharpener successfully, there's a good chance you haven't a clue as to what
actually happens when a knife gets sharpened, even if you employ a successful
formula for sharpening. You know
how. You just don't know
why. Carbide sharpeners are not voodoo. What they do is remove steel. The exact same thing that a natural, or ceramic, or diamond stone will do. However, they do so in a fashion more like a file. A file with a single, very hard edge, rather than a slew of small hard edges in series.
Again, pull through sharpeners do, in fact, work. Millions of folks use them successfully all the time. People like my Mom, who isn't a knife nut. Like most folks, she never gives any thought to polishing knife edges, never frets about angles or stones, and probably thinks the idea of observing an edge under a microscope to be absurd. All she knows is that she pulls the knife through the gadget a few times, and somehow, the knife is sharper than it was before. Which is why she and countless others have been and continue using them for years with no complaints.