ROCOF works well to keep things safe when only a small percentage of the grid demand is met by residential solar/powerwalls.
As soon as any significant proportion is residential solar (and thats already the case in some countries at some times of day) it acts as a cascading failure mechanism. As soon as any failure occurs, embedded generation sees a rapidly decreasing frequency, and rather that increase supply as traditional generators would be instructed to do to stabilise the grid, ROCOF protection requires they cease supply, making the issue far worse.
Within a fraction of a second, all embedded generation will disconnect, likely causing a near total blackout nationwide. Since system frequency that ROCOF measures is nationwide, failures won't be local to one geographic area.
I suspect these rules were made when people thought "consumers feeding energy back into the grid will never be more than 0.1% of the total - we'll always have enough spinning reserve to make up for that". Thats no longer the case, and unless the ROCOF limits are changed, and the majority of home solar/wind/powerwalls get a firmware update, expect a few very large blackouts.