One of the biggest misconceptions of bitcoin is the level of anonymity. Cash is FAR more anonymous than btc.
Not necessarily. Generated bitcoin have no transaction history and would be very difficult to link to an identity. Same with an individual that never publicly publishes an address that can be linked to their identity.
Also, cash cannot be transferred over long distances as easily as bitcoin.
Sure, but how long will these 50 btc block remain stale. If the currency takes of some of the initial transactions will be mostly anonymous (I doubt this, because I know of dbs that have been tracking ip address of connections etc.), but as they get used (is that what they're for) slowly we'll be able to track a btc and it's journey through the btc economy.
Put it this way...
When the DEA kicks in the door for a major drug bust, they get a list of btc addresses used for drug transactions. They can now go into the blockchain and look at every address that sent money to these accounts, and possibly track down the users.
If the DEA found cash.... well.... unless your fingerprints, or the bill was marked, they aren't going to tie the cash back to the users.
Make sense?
The NSA has enough computing power to mint enough bitcoins for all the US government's short-term needs. 
