A fully integrated localization program is useful when language work has become recurring enough to need more than delivery capacity. The work may still be production work, but the production environment has changed. Files return in cycles. Reviewers repeat. Terminology choices accumulate. Questions become predictable. Feedback needs to be reused. Quality expectations become part of an ongoing relationship.
The point is not to build a heavy localization system for its own sake. The point is to create a delivery model that carries decisions forward and keeps recurring work reliable as volume, complexity, or stakeholder involvement increases.
This is also what separates an integrated program from simply sending more translation requests to the same provider. The value is not only in knowing the client better. It is in turning that knowledge into workflows, assets, responsibilities, and feedback loops that make future work easier to manage.