Kind of. Ideally, if you’re carrying a weapon you intend to
use, you’ll want that someplace you can get to quickly and easily. The most convenient
places would be anywhere your arms can naturally reach. Within that context,
reaching up and pulling down a knife is a fairly natural movement.
The downside to this specific sheath position is that if the
blade comes loose it will fall out, and, in a lot of situations that means it’s
gone. There are ways to secure it so the blade doesn’t slip out, but these will
slow you down when drawing the knife, which negates the reason you’d carry it there.
So, it is a legitimate option, just not one a lot of people
actually use. It gets used to say, “look how armed to the teeth this guy is,” you can carry one there, but there’s not much reason to.