That's fascinating to watch. I am curious why this would be a faster & more robust production process compared to extrusion. I would have guessed it's easier to build it some conventional way.
Extruding non-trivially sized parts starts to require some rather extreme equipment quickly, but is done for larger bulk electrical components, pipes, and tubes.
Aluminum heat sinks are extruded regularly. Aluminum tends to be used where heat sinking requirements are less severe, as it has less ideal thermal properties. A lot cheaper though.
If someone is paying the premium for copper, they probably want maximum thermal performance - which also means maximum surface area hence more and thinner fins (as long as the material is thermally conductive enough to keep them ‘fed’ with heat anyway).
Edit: update details.