You're not factoring the most important thing about block-chain technology-- anonymity.
One could argue, considering this, that it is the perfect tool for duplicitous and corrupt behavior. You needn't look further than, say, the darker underbelly of the web to know this is true. Anonymity is always a double edged sword or to put it brutally, a necessary evil of a sort.
The practical (ethic) employment of the block-chain by governmental bodies is very real too (not all govt are corrupt). For example, the US govt is looking into the security of the voting system. The block-chain ledger, also, provides a platform for what is called "responsive, open data".
You're right, anonymity is a great part. But it's also the only argument the government has against cryptos.
Whether governments are corrupt or not, this is easy: They all keep promising transparency, now they have the perfect tool :)