Funny you mention motorcycles with gear-driven cams as being exotic. Generally correct, but I happen to own one of the cheapest out there: the Honda VFR. I sought out mine for being the last with the gears before going to a normal drive in 02. It's a glorious sound.

Anyway, that's true too, helical gear will need a beefy housing to resist that axial load. That's more weight. A pair of helicals fastened together could help bring down cost, probably, compared to herringbone, but that's added complexity. I can't claim the tech is marketing wank but the video absolutely is