What I see here are two track cogs on the rear wheel. If that's the case, then this setup can't possibly work well, because either one of the track cogs will be stripped, or at the very least be loosened from the hub, immediately. IOW, one of the drivetrains is just tagging along while the other one does all the.... driving.

A stupid way to add 1 Kg of unnecessary components to your bike, plus it will actually make the power transmission less efficient. And it becomes horribly inefficient if you don't maintain (clean, lube) the "inactive" chain.

EDIT: not sure what would happen if one used two freewheels, though. Maybe then it could work? Didn't think through that scenario.

EDIT2: I came to the conclusion, after some thinking, that this setup could work (correctly, i. e. with drive on both drivetrains) if one had cogs that aren't threaded onto the hub, but bolted or splined - and provided that the two cogs are exactly identical. And that the chainrings are symmetrical.