Avatars vs Gravatars

I have set my site up to use Gravatars, but I wonder if there is any advantage to using Avatars. Googling around I found arguments around privacy issues, but I personally believe that if one wants to remain private, they should avoid posting to public forums.

That leaves me with the risk that Gravatar (i.e. Automattic) goes nuts someday and shuts down, substitutes images, or begins to charge for Gravatars. The other thing may be that downloading Gravatar images might slow down page loads. That's all I got, and I'm totally guessing.

So, am I missing some more important benefits of using Avatars instead of enjoying the portability of Gravatars?