The flex packages are meant for grouping microservices that are deployed together in the same runtime. Routing and datasource semantics allow them to live together without violating the bounded context required by microservice architecture. Whereas adding a library “component” for customization to a specific microservice allows for customization of that microservice with clear bounded context at all levels. It also allows reuse in however many runtimes use that microservice. Therefore, while including a bean at the flex level that is a customization of a particular MS bean is possible, it is an anti-pattern because it encourages cross boundary pollution, and also makes re-arranging components into new flex-groupings (or granular) possibly more complicated.