If the embryo has a reasonable cause of action and an eager advocate, then the court will appoint someone.
There are people in this world, including some lawyers, who will sue without a moral belief in the rightness of their cause, purely out of a desire for money. That is who would ask to be appointed as a personal representative. Better not to give them the chance. Defensive medicine. There are factors behind the scenes, such as doctor and hospital malpractice insurers, affecting these decisions.