The staff one makes sense to me. When I worked at pizza hut instead of a pizza cutter, we had a big curved knife with a handle that protruded both sides. It was really nice to visually line up a perfectly through-the-center cut. The staff knife on the pic is actually very similar, just with a spinning blade.

I have a (non-TMNT-themed) pizza cutter with a handle which is like a traditional wheel cutter handle, but also splits down the center and becomes more like the two-handed “staff” one. It works very well, because it transfers the pressure on the blade from a forward 45° angle to straight-down 90°. Great for thick/hard crust.

The handle splits above the blade rather than at the center of the wheel, so there’s a bit more clearance. But still I wouldn’t say it’s an impractical design. As long as you have slim hands and keep it level.

I don't mind if you drag your knuckles through the cheese.

The sai one looks practically unusable, too. Thinking of the usual angle I use to cut pizza, the crossguards will get in the way.

I see this as a great taste, horrible execution. Especially because the one executed the best would have been better as a katana rocker cutter (which the staff isn't, as a stick with a cutter in the middle is completely different from a single curved blade, to disagree with the other commenter).

A good set would have been katana rocker cutter, sai cutter (with a longer center blade and a smaller circular blade), a staff dough roller, and I guess nunchuck grain thrasher or maybe parmesan cheese and crushed pepper shakers. But I've always been a function over form kinda guy and hate artistic choices that completely ignore function.