The little squares on your mobile have to function as brand shorthand. Sometimes you will find few letters or words. But you will probably see more pictures than letters on your device’s screen. Avatars on social media platforms are similar.
We are seeing the return to graphic pictorial icons and monograms. People want their avatar on social media to be able to fit in that circle or square. Those little avatars have to work as the full logo. If you can put your logo in a small square and it's still recognisable, you have a very effective logo.