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It is not suspension. It is a way to allow the rear end of the bike to flex a bit more than usual without putting huge stresses on a carbon T-joint. This might be useful if you have a really rigid seatpost (i.e. dropper) or are underbiking. Bear in mind that the front of the bike already flexes very differently to the rear. A straight fork with a stem and handlebar =/= a closed triangle with a seatpost on top.
That Kingpin system is all marketing crap imo, rear suspension and a rigid fork doesn't make sense. If you want more comfort on your gravel bike, get one with bigger tyres or a comfy seatpost (or buy a mountainbike).