Why a two string tether?

The image shows a two string tether above the coupling.  The two string tether is connected by a joiner that is hinged in three places.

Below the coupling there is a single tether with a single pivot point.

I am guessing that the three pivot points would capture more movement (energy) than would one that only has a single pivot point.  To me it looks like some sort of pulley system.

I am out of my depth in trying to guess how this would translate to energy capture but am hoping someone with engineering knowledge might be able to shed some light.