There can be some issues with the “horn” interfering with the seal if the flange set is too high. But certainly a less experienced installer might find it useful if the setup won’t press directly on the horn.
There was one on my toilet, but it came with it in the install kit included. I had an issue with a corroded closet bolt and my flange was otherwise forming a good seal. I used a repair kit that needed a wax ring, and a cheap one worked - as long as it was centered correctly.