I too have a personal Dropbox account and a corporate Box account. My corporate Box account has full integration, including drag and drop. No authentication required.
Dropbox doesn’t have drag and drop (at least not yet) but I cam “Move" Files from Dropbox to other locations so I don’t really care.
I’m honest, but having separate management for Photos, Vidoes or Music is the LAST thing I want on my iPad. I want to keep management for these files on my iPad within the app (just as I don’t manage photos outside of Photos or music outside of iTunes on my Mac).
We have different workflows. For the ways I work, I am really enjoying Files and it’s made a notable difference in my productivity. I was never one clamoring for “file management” on the iPad but I’ve found value in the Files app. I expect it will get more robust as services like Dropbox acquire drag and drop capability, etc. and look forward to further developments.
As for Word, as I say, when I must edit on my iPad I can do so and share my edits with my enterprise colleagues (an NSF-funded research group) in a Word doc. The rest of the time, I use the apps that make my workflow easiest and most pleasurable and then export in the format that makes sense for the intended audience and use. More and more, the “de facto standard” in my environment tend to be a link to a Box folder or a PDF file.
The bottom line for me is that I can do most anything I need to do on my iPad without my Mac and have found myself—for the last few YEARS—relying on it in my work environment almost exclusively and relegating my Mac to things like heavy photo and video editing.
I don’t agree with your statement of the objective of Files. Files, as stated in the Mac Rumors article:
“ . . . replaces iCloud Drive, offers a lot more functionality than its predecessor, and provides perhaps the best argument yet for using an iPad as your go-to mobile computer.
In Files, you have access not only to the files stored on your device and in iCloud, but also to those stored in third-party services that support integration with the app.”
This is the first version of Files. Some services are well-integrated, others are not, but I expect that to change to the degree that the service want’s better integration.