EE 6 spec

EE.5.19

A bean manager is only available in modules in which CDI has been enabled.

In e.g. a EAR deployment, a WAR module can see a EJB module. With CDI enabled in the EJB, the WAR can only see the BeanManager if the WAR itself is also CDI enabled. In cases where you want to do dynamic introspection of available beans etc, this is a bit cumbersome, especially since the introspecting code can be in a packaged jar inside a unknown WAR..