No idea of this particular flight. However CAT 3 ops are VERY slow in AUH if they require a "follow me" car for the taxi in (that is not something you choose - they require you to use it at certain vis) - as the next aircraft can not land until the previous one has been lead off the taxi way to stand.
So if there are several aircraft waiting for approach before you and they are all presumably in much the same boat in regard to fuel, there is no point hanging around and wasting fuel if you are number 5 and know there is no chance of you getting to make an approach in the time available. You might as well go to your diversion airfield first and comfortably (not arriving with 30 minutes only), top up and be ready to go home at the earliest opportunity.