Most importantly, it means that the time required for a new node to sync is vastly reduced, because instead of needing to download every transaction which has ever occurred, they only need to download transactions from the last week or so, along with the account tree which nodes are programmed to share, and they've got all they need to be a full node.
This seems to be the main thing. Bitcoin has a UXTO set, which as near as i can tell is functionally equivalent to the account tree. But it doesn't have any mechanism for sharing that information across nodes. You can run an SPV client and rely on the node to maintain the UXTO set for you, but that's about it. The next step down from there in lightness when it comes to Bitcoin is just running a full node and downloading the entire blockchain.
There may be other differences but the main problem is that with this coin being barely developed and maintained it frankly isn't worth anyone's time to analyze it more carefully and truly understand the design and the tradeoffs that are being made.
I still hold some XCN coins in the remote hope that it will be have some kind of resurgence someday but frankly it's not looking all that likely.
