Technically, it's the reverse of a coil split, splitting the two coils of a humbucker into singles, or combing two singles into a bucker, in this case.
A coil tap would split both coils part way through, lowering output and thinning the sound whilst remaining a humbucker. The two are often confused, but not the same thing.
I don't doubt the bloke's passion, it's the misjudgment of the value of his output which is the headscratcher. Most would be embarrassed to show these things off in public, let alone sell them.
I know we were discouraged from discussing his listings as he is member here, but this stuff is put out and advertisd in public, at what most would consider disproportionately high prices. If I didn't want opinions expressed, I'd play alone in the house, but I head out numerous times a week to do it in front of people. If they like what I do, great, but if they think I'm crap, well that is their opinion which they are free to express, to others or directly to me. I know that if the majority of feedback was that I wasn't any good, I might not put quite so much stock in subjecting people to my racket!
I hope, and am sure, in fact, that he enjoys what he does, but that is where the value of these really lies. As items in their own right they are laughable at best, and often a bit unsettling in their butchered and bodged nature, which is why they garner the responses they do.
Everyone needs a hobby, and it's a free country- but these listing deserve everything they get, here and across the internet.
Sorry Mark, if you're reading any of this. Passion, enthusiasm, and creative thinking are to be encouraged and celebrated. It has to be tempered with a sense of perspective, though.