An advanced use case for transforms on references are automatic color palettes. The implementation is simple and straight forward. Let's say one color the palette is ranging from 0 to 100 lightness level. Use one of the lightness level as reference (e.g. the center value at 50 lightness) and all the other values are the reference point +/- a lightness offset to that color.
Figure 1 shows the mentioned configuration, the selected .palette/brand/600 token is referencing .palette/brand/500 and adds 10 percent lightness as transformation on top.