I tend to use them a lot, they are awesome.
Besides for infill, color change and support I do use them to offer additional variants within my uploaded print profiles. I even asked for more options when it comes to using them (Toggle on/off button for modifiers).
Example taken from a scheduled update to my Life Counter 0-99:
Axles with optional sideways facing indicators, just a question of which modifiers are active or deleted.
When it comes to including a color change from one layer to the next, a modifier is THE option to use as well - instead of the “Change filament” option in the preview tab. → The calibration prints within my AMS Calibration - V2 and new Gcode by AMT_MW - MakerWorld rely heavily on modifiers for the color changes.