Board Thread:Episode Discussion/@comment-14138255-20161106163624/@comment-25936766-20161113032431

Beacon down and it's Hunters being scattered if not dead or busy protecting Vale, it's effectively 1 community of Hunters not protecting the kingdoms from Grimm (or for some, protecting the remains of Vale from the Grimm on the other side).

Which means, less Grimm are kept at bay, and stronger Grimm can go forward with less pressure and resistance.