I was googling for a quite some time, and could not find the answer to this. Here is the question:
Is it possible to manage users permissions of the lists that are deployed to the app web?
We have many possibilities to do this on host web (parent site), where we can define permissions for any users. On the app web (SharePoint app domain), we can access all deployed lists directly, and cannot set permissions for some particular users. I have different groups of users and I want them to have different permissions on the lists deployed on the app web. How can I do that, or is it even possible?
If not, what those lists can be used for, when any app user can access them directly and change the data?
No,I don't think that is possible. If you need to manage permissions for a list you can deploy it to the host-web and access that list via the app. That way the app will inherit the permissions you defined for the list in host-web.