2 question about reading cache and UI update

I want to confirm two points based on what I have read from the Guide and have noticed regarding reading cached records from store.

Based on the guide in the model section:

One downside to returning a cached record is you may find the state of the data has changed since it was first loaded into the store’s identity map. In order to prevent this stale data from being a problem for long, Ember Data will automatically make a request in the background each time a cached record is returned from the store. When the new data comes in, the record is updated, and if there have been changes to the record since the initial render, the template is re-rendered with the new information.

Since “each time a cached record is returned from the store…”, I think round-trip to the server is not really saved, only from the user’s point of view, the data is displayed much faster from the cache. ( Am I correct?)

Another thing is that once the data actually changed on the server, this background request will fetch back an updated data. I think I noticed it myself, the UI will actually make a automatic update from the previous cached value(since it’s displayed) to the new value. (this update can be noticed on the UI if pay enough attention. Am I correct?)