My guess is, there are only so many ways to be unique, building a cue, and ... if you ever want another shaft, going back to him may have been his thought.
Not to mention somewhere, someone will start saying .... ooh, the hit is better with the male pin in the shaft, and then everybody will want one.
For the record, here's what Burton himself had to say on that: "Once you screw the cue together, the pin's not in the shaft OR the butt. It's in both of them." So Scaramouche is on the right track, and Joel Hercek, like our last poster, believes Burton just wanted to be different. GF