The main limits seemed to be that you could only have one avatar and that you weren't totally free to customize its base appearance, both of which seemed to impose more accountability and trust in the system. I feel like if Suzu had rejected the Bell avatar then the system would have shuffled a bit and given her another option. Suzu almost rejected her first Bell avatar, and many groups of friends seemed to have similar themes and/or be radically different from normal human physiology.
