Yes, but (so we are told by people a lot smarter than me) there is some energy that "helps" the single bevel broadhead do it's thing. They've said in some of those podcasts that centrifugal momentum is the last of the energy to be exhausted. They compare it to a rifle bullet continues to spin even after it's forward progress has stopped. Apparently, centrifugal momentum is substantial. I assume a spinning arrow adds some level of efficiency to a single bevel head.
If the spin of the arrow did not contribute any energy after impact, then why would they say it's imperative that we match the fletch to the bevel? It must matter to some degree. Is it enough to matter to us? IDK. But the entire 12 step program to better arrow penetration depends on gaining percentages with each aspect of arrow construction. I want every ingredient of my arrow to be geared towards efficiency in penetration...even if it only helps a couple percent.
I think the spinner insert would be fine for double bevs, but it probably does nothing, or is even a slight negative, for single bevs.