Hi,
As far as I understood, the workflow to change and update a material (or object) in your local library is:
Add the asset to the scene > Edit as you like > Save a new asset in the local library > move to the correct library folder > Delete old one
The suggestion is to simply have an “update library asset” button to change the assets in the library making the workflow way faster and pleasant, like:
Add the asset to the scene > Edit > Click to update … Done, quick and easy
For me it would be useful when you realise there is a small mistake on the asset or you want to develop it more and fine tune aspects of it. I would also be specially helpful when installing libraries from others and you want to adapt it to you workflow, like for example adjusting the uv tiling of all the materials in a big library to adjust to your way of working.