I'm the opening poster.
It is true that we buy gadgets on a whim sometimes - "Oh, does that ever look neat, I have to have one!"
It is also true that some of those gadgets end up unused in a drawer. That has been true for me.
It has also been true for me that I end up loving some of my gadgers and I'll keep and use them until they are wrested from my cold dead hands.
Specifically, about the curved salad cutter: It is apparently faster than using even the most beautiful, sharp knife. Everything gets chomped at the same time. I love my salads really fine; others prefer theirs coarser, or, in the case of gourmets, each vegetable has to be chopped to a specific size.
However, some of us are not inclined to be so fussy when making our salads.
I respect the viewpoint of those wanting to chop salad ingredients with knives, making each ingredient the proper size.