Since Addison was returning to her home continent—and the journey would take an exceptionally long time if done through normal means—Silas permitted Elric to create a direct portal from the Sacred Land's temple, where Silas resided, to the Werewolf Royal Grounds. This way, Addison's newly healed body wouldn't be strained by a journey that could take at least six months, depending on their pace.
Given Addison's recent recovery, Silas knew Elric would likely slow their travel for her sake, possibly extending the trip to a full year. That's why she made the decision to allow the portal: to spare Addison the hardship. After all, Silas now considered Addison her sister.
