The real reason?
My guess is this is just a way to give the trainers something to do and earn their 130k? Therefore full union support no doubt; otherwise you are looking at demoting training captains. Shrinking airline, poor prospects for the future and a salary model based in the early 1990s must be giving them huge grief. Old kit and no money for replacements. A bit of PTF is not going to help much is it?
However, that does not mean the A330 PTF will be done in anyway but a professional manner. One assumes TCX training captains will provide the simulator sessions and not some SFI who is a buddy of a buddy and never even seen the aircraft. The skill test will have to be done by a TCX examiner if the pilot is going to fly with the airline I assume, although I may be well out of date on this. Of course a full TCX crew will be on board as well as the PTF person, the union would not have it any other way. The A330 is the easiest aircraft to land I have ever flown, unless you insist on manual thrust and get the speed slow. All the best to TCX in the fight for survival and if this helps it helps all the pilots.