It is also an example of cultural differences around the world. The last time I went in to get my drivers’s liscence renewed here in CA. the kind public servent said “now smile”.I can only speak for myself. I am not comfortable with self promotion. I tend to not smile for any pictures - especially a selfie.
I lived in Mexico for a spell and when I went for the photo for my visa I kept a very straight face. From what my friends told me, no one smiles for official photos. They said they thought it makes you seem a bit crazy.
You also see that a lot here in the USA in older family portraits. No one is smiling. Different places, different times I guess.