Not all runways (that have ILS) are cat 3 certified. My homebase airport is just Cat 2  

And pilots fly because they love it, as my A330 pilot friend told me last week:
"Nick, why would I let the computers handle the most entertaining phase of the flight?"
Makes sense, the landing is the most fun part of it all, weither your a desktop pilot or flying the real McCoy.

It's also good for the crew to land manually just  to maintain their flying skills. As they are not doing that in the simulator checks (mostly system failures and emergency landings)