A loooong time ago I wrote the buying guide and mentioned that having the tank prop rod is a good sign. An interesting side-effect of that is the occasional obsession with and surprise by the tank prop rod. Someone will mention "it even came with the tank prop rod" and suddenly 20 members will pile in and be like "OMG I never knew what that was" or "WHERE CAN I GET ONE?!?!". Usually that means I can expect a run on these things if I have any in stock. Cool, and kinda amusing, but it's not even close to being a key indicator. It's just a random little bonus when evaluating a bike.
https://en.wikipedia.org/wiki/Cargo_cult
Cargo cults are basically confusing ceremony for process. So the SV equivalent "it has a tank prop rod so it must be ok" is the equivalent "if we have things that look like planes and look like we're doing runway stuff planes will show up"
The best part of the prop rod... you can substitute anything else for it. A spring. A stick. A pvc pipe, 2x4, whatever