Pretty cool.
I can see using this with a generic 'cutting block' component that simply sits on the surface.

Also useful if you pre-build your windows / doors with trim - but it takes some setup, as it wants to cut whatever touches the wall plane through - so trim, framing, etc. needs to be pushed a miniscule amount away from the surface to be cut - otherwise your rough opening will be the same size as the trim... maybe not a big deal... but for panel layout I could see building windows with proper RO geometry embedded so the hole punch would be useful for layout.