I would expect that it works to drill holes. But it you still need motors, electronics, and software. The unit for $225 is closer to working but has no software.
I know you want to DIY it but I just wanted to point out theat the $99 unit was just the starting place.
I realized it was just the XYZ table mechanicals but I apologize if that wasn't clear to others.
Myself, I have collected several "new old stock" Nema 23 Unipolar steppers that I intended to use for a high power auto' antenna tuner project and a high power RF amplifier project. I would love to use them for a DIY CNC Mill poject instead (drool).