@Giri an avatar is something that is used to distinguish yourself.

self insertion is when you represent yourself in a form of media you create.

my avatar is a specific image of krystal. someone can look at my avatar and immediately have a very good idea of who they are talking to. this is why people tend to have unique avatars.

in the game i am making, there is a secret, funny, easter-egg character who is literally just me translated into the video game. that would be a self-insert.