In my experience, while there are some things in the backlogs that a developer can basically pick up and run with, others require input from other roles to actually address or implement properly. And then once developed, you need to test, document, and localize a feature. (Realistically, you probably want to market it as well.) Depending on your design and support model, your customer service teams may need to help organizations implement the feature effectively or may need to be trained on how to answer customer questions about that feature.