Elixir is fantastic, especially in these use cases because it allows for stateful in-memory representations of an entity with less development burdens than elsewhere.

I find it useful to have a GenServer for complex entities like state machines modeling business processes. I'm fine with the simple entities using the database schema as the state definition. However with the complex entities I still find I run into the classic ORM problem where the database structure doesn't perfectly fit the domain's pure business logic representation.