Because they are based on different criteria.
Takeoff minima is based on the minimum vis considered needed to keep the aircraft straight in the event of an engine failure and/or RTO during the takeoff roll (what you quote is cat C minima, it's 150m for cat D).
CatIIIa minima is based on fail passive autoland, and is the minimun vis (plus DH of 50') considered needed to take over and land or go around in the event of an autopilot failure. CATIIIb is based on fail-operative, so either has a very low DH (e.g 15') or none at all, and very low vis requirements (50m).