Right now you have a hard time changing a lot of materials in the outliner / blender file. If you have for example 20 different materials and you want to change 10 of them to just one materials, you can use the remap in the outline. If you mark one material, right click and say remap you are able to choose with wich material it should be replaced with. Technically it works perfect for single materials but unfortunately you can’t ‘batch’-replace. So taking the example of the 10 materials, you can select the ones you want to change and right-click and go to remap. The problem now, you have to manually click ok for every single material.
Now imagine you import a file that has over several hundred materials (because of lazy artist, error or what ever reason), clicking a few hundred times to replace a material with another would be so tedious.
It would’ve been an immens reliefe if you can check a box that says ‘replace all selected’ with X or similar.