It will save many, many hours of work.
I would have to plot everything on paper, then cut it all out by hand with scissors, then spray mount it on the foam, then cut it out by hand either on a bandsaw or jigsaw or with a hacksaw blade. (And I have to then shape all the steps...)
With the Phlatprinter 3, I just "print" in from my computer to the foam, and it will also do about half of the 3D shaping.