Is Bitcoin is waste of Electricity or much worse?

Bitcoin is a hotly debated topic. Whether you believe it is a worthwhile endeavor or not, a lot of people are investing some serious time and (literal) energy into the pursuit of mining the digital currency. It should come as no surprise that the Federal Reserve writes it off as "worse than frivolous". Is it because they are correct in their description, or does Bitcoin pose a threat to the 'almighty' reserve?

Could this cryptocurrency actually pose a threat to the private organization that regulates our country's economy? Are the powers at be scrambling to make these miners sound naive and infantile because they truly believe it is a waste of everyone's time and resources, or because they are trying to stop its growth before it disrupts their system? No one knows exactly what's going to happen as the Bitcoin phenomenon is absolutely unprecedented.

However, I find it EXTREMELY hard to believe that the Federal Reserve has the people's best interests at heart.