Managed Collections vs. Package

I am wondering what functionality a Managed Collection would provide, that a Package is not providing already.

To me it seems, that Packages provide the same capabilities as Managed Collections and add a lot of usefull functionality on top of that.

There are a few comparisons in the documentation on how Managed Collections differ from Baselines, but I lack a comparison on how they are different from Packages.

Any clarification on this would be greatly appreciated.