A chef's wakizashi is pretty much what it is. They use them to fillet 800 lb Tuna. They don't do it like a sword, more like a big honking draw knife.
More of a traditional item for high end fine dining than something that is used regularly though. You only need it for certain cuts of meat.
The only folks that use them as wakizashi's are the yakuza, supposedly, I'd also imagine they are good at motivating patrons to pay their bills also.
Personally I want one for reaching down into jars to scrape out the last of the Peanut Butter or Mayo... Then cut my sammitch, of course.