That would be handy for case work. Don't do much of that amymore, and have always used other methods to hold things vertical. Wondered why it has a cutaway base and then realized that allows you to lay the edge flat to join to another piece.
I noticed in the video that it didn't lock the workpiece vertical. There was some play that allowed the piece to rock back and forth. I think you could make something like this fairly easily, perhaps with a little more bracing. Nice item though.
The more I do, the less I accomplish.