But it ain't. And there's MMEL for dispatch.
Before dispatch (when you consult the MML) is even more restrictive - daylight VMC conditions. Very difficult if you are planning to do LVOs.
Since the final approach technically starts at 1,000 ft agl. (i.e. You may continue down ILS towards 1,000 ft anticipating that you will complete any ECAM etc.)
e.g. We may continue the ILS down towards 1,000 ft if the reported RVRs are fluctuating up and down and occasionally below minima. We may then only continue the ILS beyond 1,000 ft provided the RVRs received were at or above minima. RVRs received after we passed 1,000 ft are for information only (crew awareness) and we may continue the ILS.
Similarly if the ISIS was noticed to have failed before the 1,000 ft point then we could only do CAT I. However we are not expected to check the ISIS below 1,000 ft.