It's a good idea, but it's probably cheaper and, from an ecological standpoint better (than e-waste) to sharpen knives; a top-quality professional electric knife sharpener will set you back $170 and last you a lifetime; which is a third of the cost of the Ultrasonic's knife. Cool idea though.
I don't get it. How is buying a "top-quality professional electric knife sharpener" more ecological than buying a knife with a bit of electronics in the handle? Both are used by one person in your proposal and I would think, that it needs more energy to build the sharpener.
One does not even need a top-quality professional electric knife sharpener to produce an edge for kitchen work. An inexpensive 1500 grit whetstone suffices.
