Bitcoin is the worst investment of 2014.
No, it isn't. Many investments performed much worse than Bitcoin. Some stocks are down 98% - and that doesn't even include the companies that went bankrupt this year.
It performed worse than war hit Ukrainian hryvnia.
No, it didn't. It is down only about 60% for the year. The Ukrainian currency is down some 95%. The Russian rubble is down some 70%.
Didn't Warren Buffet said the same thing about Facebook too?
Yup. He said it generally about the Internet companies. In the late 90s. Guess what happened in 2000? He also said it about gold in 2010, if I remember correctly. Guess what happened in 2011? Yeah, he's just a stupid old man without a clue (but with lots of money). /sarcasm
I really don't think he understands the concept.
A wise investor never invests in something he doesn't understand.
The main positives are the low cost transaction fees
Speaking of transaction fees. I saw some research that currently the miners get about 0.5% of their income from transaction fees. Wouldn't be fair to say that when no new bitcoins can be mined any more, the transaction fees would have to increase at least 200 times?
it gives inherent value with security and privacy.
This is at least arguable. Regarding security, I have no hard data but have the definite feeling that a larger percentage of Bitcoin users have fallen victim to Bitcoin-related scams than the percentage of credit card users have fallen victim to credit card-related scams. Regarding privacy, I definitely disagree. Pseudonymity does not provide sufficient privacy. Recent research paper demonstrated that it is possible to deanonnymize (down to their IP address even when they were behind a NAT firewall) a large percentage of the Bitcoin transactions (some 80%).
This is like saying email has no value because we have the postal service.
It is like saying do not invest in a free e-mail provider with no revenues - which is a perfectly valid statement. (I wish I could add "unlike a postal service" but in most countries these are state-owned and deep in the hole pretty much since their creation.)