[Atixx]

Space efficiency comes to mind as well on overall usability, can't stack anything above it (aside from storage shelves way above), kitchens are rarely big enough to store such a horizontal device, let alone in places where the $/m2 is high, like many city centers.

Also practical reasons, in horizontal config it's way harder to avoid my tomatoes getting squished by leftover casseroles, let alone having a small item roll around to the bottom never to be found again.