Just as a side note from my experience with administrating a Xenforo site:
In order for GIF profiles to be only accessible by Plus, I believe devs would have to code an addon for xenforo for this to be possible. From what I know, the developers are generally not going to tamper with Xenforo unless it is a pre-made addon (EG: MineSync - AKA minecraft/website linking).
GIF profiles for all members would simply require a little bit of meddling with configuration rather any code or the addition/removal of a small snippet of code.