rpg,
I am not against using SMB to precipitate gold; I use it often to precipitate gold from a clean gold solution.
But there are times when its use would create more problems than it would solve.
Much depends on what you are dealing with whether I would use copper as elemental metal to replace gold from solution (as a recovery method), or use SMB to precipitate gold from solution as a refining method, or use some other reagent like ferrous sulfate to precipitate gold from solution.
Copper will recover gold where there is a problem, like too much nitric, or a solution loaded with base metals where a chemical reagent like SMB would possibly not work or would just be more problems.
SMB would work better for refining where you have eliminated the base metals and have fairly pure gold in solution, and have also removed the oxidizers like free nitric acid or chlorine from bleach, or chlorine and oxygen from use of concentrated hydrogen peroxide.
There are several reagents that will precipitate gold from solution, and they each have there place in refining, I cannot think of any I am against using, but also believe there are places where one should be used rather than the other depending on circumstances, I also do not believe me or Laser Steve would disagree of when one should, or should not be used, other than maybe personal preference or some other reason like choice at that time.
You have chosen a good process to proceed with your problem, the copper in the added foils will precipitate your gold from solution as a fine powder, as the copper II chloride leaches copper from the added foils, just be careful to let this powder settle well when decanting, and washing your gold.