Yeah, I believe they are referring to power GFX, not the aura, confused me when I first read it too, I thought "You literally choose to put an aura on your character, why would there be a Minimum/No FX option?"
I agree with having the option for powers GFX, only it'd have to be an Options setting that applied to buffs placed on your character by others since you can't make other players chose the option in their powers customization. Makes me wonder that if we add a comment to our own costume files regarding said power even if we don't own it, would it have any effect. Hmmm...
Sadly, adding the parameter for minimal FX Ice Shield to your own power customization file appears to have no effect, I even went to a trainer and loaded the power customization file just to be sure. Fortunately is doesn't seem to break anything either.