Ozone does very little to sanitize the pool when it is on and nothing to sanitize the pool when it is off.
I am in season 5 with salt and OK flagstone with no visible erosion attributable to salt to my flagstone or my pool deck. I do have some flagstone with some pretty significant erosion but it isn't near my pool. Stone that is going to erode will do so with or without saltwater near it. More info in my build thread, link in sig.
More here on UV and Ozone, Alternative sanitizers and pools--The Truth!!
I am definitely doing SWCG having struggled in the past with Chlorine only pools, and my stone around my pool is going to be Shell Stone, I am guessing that Salt will have zero affect on that stone, since its origins are from a salt water environment.
That's the plan anyway