Prototype #2 has many improvements over typical CNC setups. First being collapsible. Now people (like me) who can't afford a permanent space to be used for a CNC can store the machine in a closet when not in use. It is easier to carry it from point A to point B as well, carrying lighter parts than heavier wholes. Though being collapsible creates issues as well. It can take longer for setup and has to be aligned every time to make sure the dual X axis tracks are parallel.
A second improvement is having an open table, though some CNC machines have this as well so it's not as a break-through. This does allows for oversized materials to be placed through the CNC, like a tree log or long lumber.
A third improvement in prototype #3 is it allows materials/stock to be worked on from above the surface, like any other CNC machines) but also below the surface. I can do engraving work up to 6" below the surface if I wanted to. This means I can prop my machine on top of an oversized picnic table and engrave on the table top. I can technically mount the machine to a living tree and do some work on it if I wanted to.