Re: Government should implement blockchain technology to prevent corruption.
Blockchain is a good technology that will be use as a tool of transparency to every transaction being done. The government should know and develop a system like this on their system. This will eradicate corruption or transactions being made under the table because there will be a transparency on every transactions and how much money is involve. The budget of the people will be obviously utilize to its intended purpose. Would you agree with this idea?
But we can't expect a corrupted government to take steps for anti corruptions. 
As you said the blockchain can be used in all the transaction for the government related which can help us to have corruption free transactions but the politicians need to implement this system but if they do then they can't make money anymore so they will never do this.
Since bitcoin(crypto) are not legalized in some countries also this your proposal may be not effective because as of now it is hard to implement this law to the government since bitcoin was against to them. But who knows it will happen, time to time bitcoin users will be having regulation to the government and blockchain is a part on that as well.