I am looking at making some wedding ring spinners and it calls for using leader material vs taking line of a spool. My questions is are they the same or is their an advantage to using leader material for making these lures.
Usually the same. Sometimes there's a difference, but usually not. Save money and use that last bit of line you've got left over after filling your spool. Of course, make sure its not old. Spending a couple more dollars for fresh line is better than using old line just for the sake of using it up. Those leader spools are more convenient to carry around, sometimes, but they definitely are much much more expensive than the 300yd spools.
The leader material is usually stiffer but more abrasion resistant. Other then that ususally the same. If you fish is areas where you're leader takes a beating then the "leader material" might be worth it, otherwise spool line is fine.