You forgot to add the benefit of the newspapers is that it also will break down and add organic matter to your soil, along with the leaves.

I tried this same technique a couple years ago with an area next to the driveway that was overgrown with weeds. I laid down a couple layers of cardboard, then 8-10 layers of newspaper and topped the whole thing with about 4" of sandy loam. Then planted flowers there. Everything grew like weeds, but it wasn't weeds, it was lantana, dahlias, scabiosa and daylilies.

Last fall I had to move the whole flower bed when we had the driveway graded and the soil where the cardboard and newspaper had been was rich, dark earth chock full of earthworms. Now that's great mulch too! Cheryl