Laura Graham-Brown shows another way to use variable libraries:
One of the popular low-code tools within Microsoft Fabric is the Gen2 Dataflow. Power BI report builders already know some Power Query. So armed with this knowledge is a popular starting point to load data into Microsoft Fabric. Adding values from the Variable Library in a Dataflow is an obvious plan to make it more future proof and to work better with Deployment pipelines.
I will confess the first time I tried these I could not get them to work till I read the instructions correctly. So they do work just understand the limitations!
To be fair, following instructions is one of the most challenging things to do, it seems.