The difference between the Greek writedown and a "real" default (as yes, technically Greece has defaulted) is that a writedown is negotiated before the fact, similar to those debt-relief services you see on American TV. There's a reason your creditors will agree to essentially cut some of their claims on you if it means saving you from bankruptcy, simply because the creditors then at least know what they're getting, and will get it without a "fight." It's similar to why so many companies will settle lawsuits, even lawsuits that they have a decent shot of winning, rather than take it to court. Bankruptcy or defaults on the part of the debtor create more uncertainty than if you simply say "we'll relieve some of that debt and never lend to you again,"
Essentially, even for completely selfish purposes, the Greek creditors want a solid, scheduled guarantee of how they'll be compensated, rather than the chaotic scramble that results in a disorderly default. Then factor in the fact that a Greek default would be bad for so many different groups of people all over the world, so the creditors were under significant pressure to accept the terms, but likely would have done something similar anyway.
Soleron answered the rest of it. If people think the current situation in Greece means they'll be the European Central Bank's bitch, it would be all the worse for Greece if they defaulted otherwise, as then the country would basically be run by the Central Bank and the IMF and have to do austerity much more severely than they currently do.
Monster Hunter: pissing me off since 2010.
