I think the criticism is that it's less likely to build an ecosystem like a Gnu Public License would (see https://en.wikipedia.org/wiki/RepRap for an example of a 3d printer that very successfully used the GPL). The CC license prevents large corporations from stealing the design. But it also prevents someone from 3D-printing parts and selling them on a small ebay store.
Seeing the dissembled printer makes me want it regardless of license tbh