hahaha, no! don't buy it unless you need it!
try rotoing something with motion blur. you will find that the blur is different all around the object. On one area, a feather of 20 might be perfect, but on another area, 2 might do the trick.
This is impossible with a single mask using AE's default mask tools. There are work arounds, but its just easier to have a non-uniform feather edge to control it.
seriously, though, don't buy it unless you need it. I've been waiting for it for years, so I didn't hesitate.