It gets rid of any chance of heal drag, you can turn insanely small corners with no trouble, they're great fun. You don't need to get this fancy with them though, no need to take out the sides and all around it, just the bottom bit. You can just take a graver sharpened with something like a lindsay template and then grind a small divot into the bottom of the graver right behind the heel with a grinding wheel like they used in the video and polish with a diamond wheel. Lets you spin on a single spot and never get heel drag, also handy for clearance for stuff like the raised edges of coins.
Looks like a good idea, but the music put me to sleep half way thru the video.
I don't see how this has any great advantage over a properly sharpened square graver.