I think I'm familiar with the difference between a connected app definition and its consumption:
As the vendor, my Connected App definition lives by himself in a dev org forever:
For the users, in other orgs they can see (or revoke) any Allowed apps from their user record:
The Connected App does not need to be in the package for users to 'Allow' access to it.
But Salesforce also make it possible, in a release org that has a namespace prefix and a managed package, to add a Connected App definition to a Managed Package:
Packaging a Connected App
After creating a connected app or a new version of an existing app, package it to make it available to users on other Salesforce organizations. You can add a connected app to a managed package in the same way as, and along with, other components such as custom objects, Visualforce pages, or Apex classes. This makes it easy to distribute a connected app to other Salesforce organizations. As a packageable component, connected apps can also take advantage of all other features of managed packages, such as listing on the AppExchange, push upgrades, post-install Apex scripts, license management, and enhanced subscriber support.
What is the use case for this, as opposed to the definition existing only in the release organization?