I like bitcoin, and use it from time to time, but it seems like the blockchain has the capacity to make transactions even more trackable trackable than transactions at a bank.
For transactions you want to be sure will remain private, it's probably still best to cash, or a physical, cash substitute. (Precious metals, barter, etc.)
IHMO, it also has the to shore up the current banking system (good, bad or indifferent). Instead of pulling dollars out of accounts and holding it as cash, people can buy bitcoin; keeping those dollars in the banking system in the process.
I also have concerns about whether cryptocurrencies will continue to hold up when quantum computing goes mainstream. It's probably a long way off, but it's still something to think about.
Another concern I have is the possibility of the entire global banking system being put on a blockchain. A blockchain based legal tender currency could spell the end of financial privacy for anyone forced into such a system.
RE: Brace yourselves...Bitcoin is hacked by the CIA