An example ; when we start throwing smart nano on the grass, to see how each blade of grass is doing on your lawn. Well, each nano is going to need an IP address, and so will all in the neighbourhood. And that's just the grass.
What about when some scientist wants to track sand dispersal patterns, on a beach, after a hurricane? And wants to have each grain of sand tagged with its own nano hitchhiker? Just think of the IP addresses we'll need then!
And even medicine. What if we want to interally tag each cell in our bodies with nano? What if we want to bioengineer our body, so that each cell has its own IP address? And can report health/condition?
No, we need more, more more IP addresses! So many more.