Seems it would be expendable in that use case, but "work properly" seems to be the catch. On MacBreak Weekly this week, Adam Engst was recommending listeners immediately disable that feature when Sierra launches, as he's been finding it buggy & running into data loss situations.
I need to rethink that soon. If macOS Sierra's (to be released next week?) similar replication features work properly, doesn't Dropbox become expendable for customers playing exclusively within Apple's ecosystem?