The main advantage of using a microservices architecture in application development is its flexibility and scalability. This approach involves breaking down applications into smaller, independent services that can be developed, deployed, and scaled individually. Each microservice addresses a specific business function, allowing teams to work on different components simultaneously, which accelerates time-to-market. Additionally, microservices enable easier updates and maintenance since changes to one service do not necessarily affect others. This structure supports resilience and facilitates cloud-native development practices.