Standalone app to disburden browser and help focus, mac notifications available, same UI as browser version
No offline usage and buffer - this would be critical for real app advantage
Understandable that offline usage is probably on feature backlog and not yet implemented as this needs complex sync management. But until then this not much more then a browser substitute. If you are on the road often and try to work with Trello this is painful. Internet on the road (eg trains & flights) is never stable and Trello is very sensitive with connection.