The US Department of Defense went quite a bit further. They created the Condor Cluster in 2010 which was comprised of 1760 PS3s. At the time it was placed 33rd worldwide for a supercomputer.

https://phys.org/news/2010-12-air-playstation-3s-supercomput...

The marketing win of being able to say "these are so poweful, the military literally uses them in supercomputers" certainly more than makes up for a hundredth of a percent of consoles having a zero attach rate.

I would be curious to know more precise numbers. My intuition suggests that when Sony sells millions of them, the number diverted for non-gaming purposes is maybe thousands or tens of thousands.