Found a few issues so far:

Install on mac results in a folder copied to Applications, instead of single 'fat' binary.

Opening a file from the briefcase works, but results in a screen with a 'loading' graphic remaining. This can safely be closed, but is confusing.

Opening a file from briefcase in certain application on mac results in a copy being downloaded to "Downloads" (on mac) and then opened. Changes are of course saved to the offline copy. This is extremely confusing to users and (mostly) defeats the purpose of offline file access.

My 2ct.