Similarly to picture loading, this feature would be great:

Currently, systems in worlds with profiles (such as social worlds, leaderboards and such) rely on complex camera systems periodically capturing a single frame of the user's avatar in world, it is unoptimized, inaccurate, lag often leads to it being plain wrong or showing another user, etc

With Udon access to profile pictures and an event on profile picture change, this would allow the users to have their chosen profile picture that vrchat already provides appear in those without the use of such systems, and would make such social profile/displays be a lot more interesting.

Many worlds that focus heavily on social features and meeting people could heavily benefit from such feature.