First of all, a warning that materials used on your project have updates in the library will be more than welcomed. As multiple users pull materials from a company materials library, it is possible at a certain point that you are opening an old project and you may not be aware of a possible change.
At this time, such a change may go unnoticed.
It will be nice to be able to update the materials in the current project with the updated version(s) in the library faster than is now possible.
At this point, if you made a change to a custom material, the existing material in your projects will still have the originally defined properties - which is the expected behavior.
When you have lots of parts and materials in a project, it will be nice to be able to:
1) select objects and have a right-click option to update materials from library
2) do a global update for all the parts in the project.
I hope that users that work in projects with a large part count will appreciate this.