Final answer:
The AdWords API is used by developers to automate and manage large-scale AdWords campaigns, facilitating efficiency and customization for advertisers and agencies.
Step-by-step explanation:
The AdWords Application Programming Interface (API) is designed for developers representing large, tech-savvy advertisers and third-party agencies. It allows them to integrate their own applications with AdWords to manage large, complex AdWords campaigns more effectively. Using the AdWords API, developers can automate the management of multiple AdWords accounts, customize the reporting, and build applications that manage inventory, among many other tasks. This ensures efficiency and scalability in managing large volumes of campaigns, leading to more tailored and strategic ad management.