Use of Layers.Modify?

I’m wondering what the use of Layers.Modify is-- it doesn’t seem to be necessary in this case, for instance (changing a layer’s color in python):

import System.Drawing as sd
from scriptcontext import doc

def add_layer(name,color):
	myLayer = name
	layerInd = doc.Layers.Find(myLayer,False)
	if layerInd == -1:
		layerInd= doc.Layers.Add(myLayer,color)
	return layerInd

if __name__ == "__main__":
	layerInd = add_layer("TEST",sd.Color.Black)
	print layerInd
	layer = doc.Layers[layerInd]
	layer.Color = sd.Color.Lime

If you uncomment the last line the code will run just fine, but I’d like to know in what cases Modify is desirable.