Well, apparently they are good for incidental protection of wildlife. Myanmar's increasing openness to global markets is likely to cause major impacts to their wildlife. It's interesting to note that the DMZ is also a local biodiversity hotspot in the Korean peninsula. It's almost as if a lack of humanity means that there isn't a destruction of natural processes, which means that there is an increase in biodiversity... Not so strange.
However, does this mean that ecologists and conservation biologists ought to support dictators? Uhh.... no. That's not even a question. Increased biodiversity hotspots can be maintained through local governance and conservation efforts throughout the nation. Enforcement of entry and use bans (as well as creating a focus on the trade of wildlife species when so many other social worries exist) would likely be difficult in a country that is emerging from a military dictatorship. However, instead of running wholeheartedly after urban development and resource extraction, it might help a country to develop and maintain a strong sense of pride, ownership, and stewardship of their natural resources, meaning that - although their economy may grow more slowly - they will maintain (hopefully in perpetuity) their natural heritage.
Of course, looking at the trend of how these things progress, I'm not going to be holding my breath.