1. To get an overview of whether or not we have planned user stories for all the acceptance criteria.

2. To track changes in acceptance criteria as they sometimes change.

I will try to explain in feature words;
As a tester I want to know which acceptance criteria that I can test (meaning that work I know that work has been planned for the AC and it is also done.)

Right now acceptance criteria can be written in a text field which is not good enough for us. We cannot track them and we cannot create link to both a feature and user stories. We are attempting to use Objectives for this purpose as they have the "many to many" possibility. But they are not optimal.