When Copenhagen received the Tas.devils, one of the main arguments for them getting the species was that they would built a breeding facility, which they did, under the presumption that it would be the start of an eventually self-sustaining non-Australian population. It's why they –from the start– have had a handful of exhibits for the species instead of just one. When the move was first proposed by Tasmanian politicians, it appeared to catch everybody by surprise, the receiving zoo too. It really did not seem like the Australian breeding centers/people in charge of the local program had a ready plan for sending animals abroad, although the local captive population already was large. A princess was the catalyst, but a reasonable management plan for the transferred devils was still necessary. So, an agreement was reached where Copenhagen would be a "test" facility; to see if sufficient breeding could be achieved outside Australia (northern hemisphere–opposite seasons, short lifespan) to have an eventually self-sustaining non-Australian population. There had been breeding in earlier decades at other non-Australian zoos, but never at levels approaching self-sustainability and each of those populations invariably died out after only a few years. Old devils as "ambassadors" was a more recent idea, only initiated years after Copenhagen had received and begun breeeding devils as planned.
We've all seen politicians/authorities around the world that sometimes make rather peculiar and illogical decisions, also when dealing with animal conservation and management. Do I feel confident that Australian politicians/authorities will continue allowing transfer of devils (incl. old "ambassadors") in the next decade or more? Do I feel confident that American politicians/authorities will continue allowing transfer of sea otters (incl. sterilised "ambassadors") in the next decade or more? No, not at all and if someone had asked me about European politicians/authorities the answer would be the same. In other words: as long as non-Australian zoos rely 100% on continually receiving devils from Australia, they are always just one illogical political decision away from losing the species again. With a species as short-lived as the devil, this could happen fast. However, once self-sustaining populations have been established in more than one country/continent, it reduces the risk of the species disappearing from zoo's in all but one country based on the whim of politicians/authorities in just that one country.
This leads to related discussions. I have heard some that suggested that devils outside Australia are of little value because they're quite unlikely to be transferred back to their native country in the future. However, I suspect most people on this site recognize that zoo animals are not only for conservation, but also education. Otherwise zoo animal diversity could rapidly be downsized. For example, many of the
non-Australian mammals kept in Australian zoos either are 1) not threatened, 2) unlikely to ever be returned to their native country, or 3) rely on "new blood" from zoos in other continents because of the very small local founder population. The first two and to lesser degree the third are shared with zoos of Europe and North America.