Changes view helps you see the change happened between two snapshots or versions of your source code. Changes in various ratings, improved or deteriorated components in various aspects such as design (anti-pattern), duplication etc. can be easily seen here.
Consider you want to audit the changes in components between two snapshots, this view allows you to do so. You can see the changes in ratings or metrics of each component.
Filtering allows you to list improved components, deteriorated components, fixed hotspots, created hotspots and more.