Cavalry class progression

During BF1 Beta my cavalry class ranked up but have no idea what that means.I saw no apparent upgrades ???

I had the same experience with both Medic and Support class… Saw nothing obvious but I guess its to do with attachments etc in the main game (like in hardline where you get certain scopes/skins only after so many kills)

You had to go to the careers page (external to the game) in order to unlock stuff