What's with the new style of barcode on grocery store coupons?

I've noticed that grocery store coupons have changed. Many of them now have a thin bar running through the middle of the code. Anyone know what this is for?What's with the new style of barcode on grocery store coupons?
This is known as a GS1 DataBar Stacked code. There are two separate barcodes stacked one above the other. The thin bar running between them helps the barcode scanner keep the two codes separate.What's with the new style of barcode on grocery store coupons?
Maybe it's to make the coupons harder to copy.

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