The hybrid layout, and the sizes of the gears and sprockets used, is all about packaging the drive system into as little space as possible. In a traditional all-chain setup, the sprockets on each camshaft must be twice the size of the sprocket on the crankshaft, so that the cams spin at half the speed of the engine. Even using the smallest possible sprocket on the crankshaft, the camshaft sprockets can end up large enough that they force the camshafts to be placed farther apart than desired, affecting overall size of the cylinder head. With a system using all gears or a combination of gears and chain, the gears can be used to obtain the 2:1 ratio, and smaller sprockets or gears on the camshafts can be used. This, in turn, allows the cams to be closer together and the cylinder head to be smaller. In the case of the Panigale’s hybrid drive, the chain/sprocket part of the drive accounts for some of the ratio, while the gear part accounts for the remainder. Note in the image that even in the Panigale’s case, the crankshaft sprocket is as small as possible given the size of the crankshaft at that point; based on that, and all-chain drive would definitely push the camshafts much farther apart.