Difference between Content Pack and App workspace

Hi there , here is a general idea of how working with apps ( I am not including here the differnce with Groups)

Here is how you should work with Apps ( In general) 

Create an App workspace , this is the "working enviornment" - add their pepole that will manage & review the reports under the app. 

Afterwords , add content you want . 

After finish You can publish the App to the organiztion or specific users. 

Then here is the nice part in apps - you have a "Stage enviorment".

If you or one or the users want's to make change to a report you will do it in the App Workspace , Only until you will "Republish" the app again the users of the app will see the changes. 

Hope it makes some things clearer. 

Shmuel