I'm in no way suggesting they should or asserting China's great because they have standards when it comes to taking political prisoners... Nor am I stating that China is so barbarous that I would expect nothing less of them... I just don't know and wonder about the answers to these questions?
Sounds like the former prisoners you met still hold the beliefs that probably made them prisoners in the first place. They're still monks (practicing I assume). They're now back in their country of origin?
What was accomplished?
Time? The best I can come up with is that it bought China time to begin and continue ethnically cleanse (displacing, not killing) Tibet (as well as other regions), while not breaking any international laws or attracting enough negative attention to jeopardize any foreign trade or financial relationships?
Look at the news about what's supposedly going on in Xinjiang... China is getting nothing but bad publicity, but no international entity is pulling out of those areas or others in China because of what they're supposedly doing to the Uyghur population. If anyone is leaving China, it's been reported that it's for unrelated reasons.
If China just disappeared these people instead of putting them in camps, would the world react any differently? It doesn't seem like anyone has been able to substantiate these claims about the resorts (concentration camps), so how much harder would it be for China create the same level of control around a massive park or recreation area (polyandrion or burial site)?