I think we can agree that the vertical wedge in building construction will fail earlier than wedges pressing across the grain of the post. It's telling that in the one video I notice that figure who is something of a celebrity in the woodworking scene mostly connected to folksy furniture, but I'm really not so familiar. Anyway, I know the joint as shown as the standard connection of the stretchers to the leg construction of traditional furniture makers workbenches allowing them to be easily disassembled and in that instance it makes perfect sense. This is the very construction of my own workbench in fact which will never get 4000 lbs. of tension applied to it.