Kristyna Hughes has an interesting use case for row-level security:
Making multilingual reports in Power BI requires a lot of different elements. Translations can be added to PBIX files to translate column names, visual titles, etc. but these translations will not impact the data itself. One way to translate the dimensions themselves (star schema introduction) is to have a translation table that contains a display language and value column for each ID of the dimension. In the example below, the translation table would replace the original table and we could apply RLS to the Language column.
I think this is a clever use case for row-level security.