I just learned that by default, Oracle does not grant the 'create session' privilege to new users. No problem, I can do that myself.
Anyway, I'm curious: why would I want an Oracle user without 'create session' privilege? What can it be used for? There must be some non-obvious use. My first thought was running database jobs, but AFAIK they need this privilege, as well...
It could be used for a schema with some shared objects, rather than a real user.
Other users (who can create a session) would be accessing the tables and procedures owned by that user.
But according to Tom, it was just a way to lock an account, before accounts could be locked.