The Metadata Tool, most of the time overlooked, is a pretty handy Ci Tool that allows you to modify elements Classifications and Properties quickly. Without this tool, you would need to access the element settings to modify them quickly, and this can slow down your workflow, especially when you have to do this over a few hundred elements, or even more.
The MetaData Ci Tool is a Palette that will allow you to modify that information on the go, by just selecting the desired elements and modifying the values within the Palette.
You can either modify element properties or the classification assignment. If multiple elements are selected, but they have different classifications assigned, you will see the properties that are not in common for both types highlighted in blue.
I hope this information is useful for you to know a bit more about MetaData.