Besides being just a nice to have thing, having our production code in a single named module likely gives us access to the power of sealed classes and interfaces. As long as our code is in an unnamed module, the following restriction applies (see JLS 9.1.4. Permitted Direct Subclasses and Subinterfaces):

every class or interface specified in the permits clause of I's declaration must belong to the same package as I, or a compile-time error occurs.

We expect that once we put all the code in the same named module, we will be able to implement sealed interfaces / extend sealed classes from different packages, even if an application does not add our module to the --module-path.

Addressing the source code notes tagged with TODO-HIBERNATE-52 is in scope of this ticket.