Very little in the way of commentary from me on this post, because the video says it all. This is my favorite class of tool: the cow's tongue rib, or 'gyubera', in Japanese. This is a traditional tool used by Karatsu potters, and it was developed for use with short, difficult to throw clays and crushed stone bodies (like porcelain).
Like anything, they take some practice, but will make your life way easier! I hope you enjoyed the video!