Has anyone tried this kerf-finishing tool for half-blind dovetails? Is it worth buying?

Once again, Rob has mesmerized us with a dazzling demonstration of its use to punch out the remaining triangle of the kerf after sawing (at an angle) around the pins. It leaves a kerf straight down, all the way to the gauge line. To see it in action, start at 26:23 in this video:

https://www.youtube.com/watch?v=sx0tc-UGRXY&t=1646s

Here's the listing of the tool:

https://robcosman.com/collections/sa...mans-kerf-x-10



Expensive? Absolutely. Gimmick or useful? That's my question. Seems like it would simplify chiseling because you'd only need to pare out the end lap. Anyway he sure makes it look easy.

I can't believe I'm considering spending this much money for a tool like this.

I'll bet there are some here who know of a simple, inexpensive alternative to the fancy Kerf X-10. Or let's hear from the purists who only chisel at this step. Or maybe we'll see a testimonial for the X-10. Curious to hear.