It's not hard to make a mill that can cut shapes into a block of styrofoam. If I stretch I can maybe imagine some industrial uses for a styrofoam-only CNC mill.

It's not hard to make a mill that can cut shapes into a block of styrofoam. If I stretch I can maybe imagine some industrial uses for a styrofoam-only CNC mill. (Moldmaking?) But what would a regular consumer use it for? "Serious" just means the ability to cut more useful materials, like wood or steel.