The advantage for manufacturers, when the technology matures, will be in not needing specialized tooling--Ruger could run say, a 1911, a P345 and a 10/22 one right after another on the same line. Significantly less need of human involvement in machining ops, in theory the only thing you need people for is cleaning the printer heads periodically.
For the home-gunsmith set, the advantage is that they can print as many as they want, knowing that they've never been registered anywhere and thus aren't "in the system"--just like when you finish an 80% PCR.
BUT... the rub is ultimately cost. This exercise reads to me as a pure "Can it be done AT ALL?" rather than a "Can it be ECONOMICALLY done?"--proof-of-concept, a first baby step as it were, and now that they know the technology works they can start looking for ways to make it less expensive. Combine this with plastic / bio SLP, and... well, THIS is our road to Star Trek replicator technology.