Vista isn’t a particularly good place to work. It’s haemorrhaging pilots in Europe as conditions there are poor and compared to other spots in the US it’s not particularly great either.
They are desperate for pilots and rather creative with doing whatever they can to get more, hence this E3 program to get aussies to be based in the US but probably spend most of their time out of it.
As a DEC it’s probably not a terrible place to be if it does get you a green card (if that’s what you want). But I would fully expect them to dangle that option in front but rarely ever get it done, as the moment you have it you go anywhere better (which is most of the US market atm)