You're 100% correct. Blossom/trello/jira etc all suffer from the same data replication problem, though blossom is a pretty product. It was among the products we tried to use before deciding to build ZenHub in the first place! Huboard and Waffle assuage this somewhat, but they still require your team to jump around between different tools, causing workflow fragmentation. ZenHub is the only product that avoids both flaws.