Sensation blades

The 2 sensation mowers I recently purchased have a good size metal disk used in conjunction with the mower blade. 1 mower had a very narrow light blade with welded "wings," and the other was what I would consider a newer, modern blade that was twice as wide and heavier. My question is, from what I could find out online is that the disk added mass to the smaller blade for the flywheel effect, but if using the newer replacement blade that is bigger/heavier is using the disk still necessary? Thanks!