If you have one or more snapshots of a filesystem, you can now take advantage of the saved metadata to do fast difference checks between them, or with the current filesystem, rather than having to manually traverse the filesystem with diff -r or rsync. It's not always two-second fast, but it is certainly convenient when you already have a snapshot made.

The only downside is that it does not tell you the actual file content that has changed, only that the file has changed overall. Even so, I have found this to be quite useful on occasions. For example, if there is some install command that you are not 100 percent confident of in what it does, creating a pre-install snapshot and then a diff, can tell you with certainty what happened on even a very large filesystem, with minimal system impact.

It can also tell you which files have merely been renamed whereas a normal diff would tell you "oldname file has been removed: newname file has been created".

Technically, there...