CDI bean in JAVA EE

Recently I have seen CDI bean uses in DDD Sample Project "Cargo Tracker". Where a CDI bean was used with @ApplicationScoped annotation with Entity Manager for data access repository. My Question are as follows:

Is it a good practice to use Entity Manager with CDI bean instead a @stateless bean(EJB)?

What benefit we get by using CDI bean with Entity Manager without container managed approach?

Exactly when should we use CDI bean instead stateless container managed bean?