After some digging through the code, apparently that checkbox switches what the roll button does (or rather, hiding one roll button and displaying another), swapping between exploding d10s and not. However, the way it's set up could cause issues with someone creating macros manually. Both roll buttons have the same name, so you can't be certain whether a macro pointing at that roll button will be using the exploding d10s or not (and checking the box won't make a difference). Also, the non-exploding version of the button on the 4th and 5th row in the section are same the name as and pointing at the attributes for the 3rd row.
