"Synthetic cell factory" seems a hyperbole, because what they make are not living cells, so there is no danger of their proliferation.

What they make performs a small part of the functions of a living cell, i.e. they make assemblages of nucleic acids and enzymes that synthesize proteins.

This is the actual definition of the PURE systems that they fabricate:

"PURE (Protein synthesis Using Recombinant Elements) is a fully reconstituted, cell‑free protein synthesis system containing only purified, recombinant components for transcription and translation, with no cellular lysate contaminants."

So their factory is better described as a factory of "synthetic non-cells", not as a factory of "synthetic cells".