Android apps generally work well on Chrome OS these days, but there was one nagging issue left unresolved - file management. While you could access the Chrome OS Downloads folder from Android apps, the Chrome Files app couldn't see the entire Android file system. At long last, that is finally changing.
François Beaufort, Chrome evangelist at Google, announced today that an 'Android files' menu option in the Chrome OS Files app is in development. You can try it out right now, by enabling the new #show-android-files-in-files-app. Presumably, that flag is only available on the development Chrome OS channels (it didn't appear on Chrome OS 66 on my ASUS Chromebook Flip).
The ability to view Linux files from Chrome OS was already being worked on, so it was a bit strange that Android data wasn't accessible in the Files app until now. Either way, I hope it comes to the stable branch soon.