My guess is that as it puts the inlet (assuming outside-in flow like normal filters) near the top of the filter cartridge and the housing is semi-vertical it may help keep the filter mostly full of oil when the car is off if there's an anti-drainback on the inlet side.

I don't know if that exists, but it is german emgimeering.

Spin-on filters have no-such structure in them and work fine, but I've also never seen one mounted drippy-side down.

 

the Jeep 4.0L - I think there's still 1 or 2 running around out there ...

 

but I've also never seen one mounted drippy-side down.

76 MG Midget big oily mess