I had the idea, probably not original, to incorporate a simple woodburner and stumbled across this:

I especially like how the packaging appears to become the work surface.

There’s a post on these forums (look in the gallery) of someone using a woodburner tool on an MPCNC.

As for the Pyroprinter…

$990 for a few steppers and a hot wire.
Claims like “sensor makes fire impossible”.
They also claim that lasers can’t do grayscale, well some lasers can.
Proprietary software, windows only

I like the wire heater, and the simplicity of the design. I think the hot wire is a smart choice. It would be neat to basically use a printer hot end, with a point instead of the nozzle. Then you could set the temp and get pretty consistent temps.

Can you tell how they are moving in Y? It’s hard to see the details but I think it’s rollers, maybe a toothed wheel and stationary rods that act like a belt.

It’s definitely a threaded rod. I’m not sure what they are using to move along it though. I’m assuming it’s the right stepper, which is angled down. I think your guess of a gear attached directly to the motor, riding on the threaded rod is a good one.