What is the difference between PCID : 0 and PCID : 6 frame structure?

Hi Experts,

What is the difference between PCID : 0 and PCID : 6 frame structure
https://www.sqimway.com/lte_resource_grid.html

from the frame structure it seems same

1.If so what is the significance of having many PCID’s with same frame structure?
2.PCID is used only to derive CRS positions ? Or does it have any other significance