Say you have a shadow that you use on three different button or card components and you want to change it for all of them:
Currently, the user would have to manually go through each individual shadow effect and double check each of the values.
Ideally, one would be able to store it with a name like “Card shadow” or “Button shadow” in order to update all of them at the same time, and to have everything more organized.
Same goes for grids (if you use the same 4-column phone grid for i.e. the PinePhone and the Librem 5 etc)