There are many people who only have their pets and no family and want their pets (family) to remain with them after death. It is just as heartbreaking losing a loved pet to some, as it is to lose a family member and I believe there would be no threat to the environment to allow this.
Those who have never had a partner or children can look to a pet as the only love they ever had and I believe it would give them a greater peace of mind if they knew they would always be together.