From what I can see in Files so far (though this may change), it's very much like other existing file managers (Documents, Goodreader, etc), where you can access files in iCloud and other cloud storage providers (anyone that implements the FileProvider extension), and organize and tag files, and allows you to move files to local storage, but it doesn't do anything new in allowing you to "see" the files within individual apps. From apps you would still need to either share to iCloud Drive or drag-and-drop to the Files app to move files there. I would love it if apps could opt-in to having their local files visible to the Files app, but I don't see that happening yet.
I think that's going to be the biggest improvement, is the ability to drag-and-drop multiple files.
We will definitely be watching and working to implement everything we can to improve file/media management for LumaFusion using iOS 11's capabilities.
iPad Drag & Drop feature available in ios 11. Try this how to use Drag and Drop in iOS 11
. See this Video : https://www.youtube.com/watch?v=Q26pu4AT--Y