BlockChain - A Panacea or just a bubble ?

Up lately, I have been hearing about bit coins, block-chain,cryptocurrencies a lot. Even the guys who don't know a thing about block-chain or bitcoins use it very casually.They are the future !, they are the web 3.0, they truly change the way people exchange information etc.  I agree, they have a huge potential.But I don't think they are the solution for all problems. They are good for maintaining the digital identities like birth certificates, passport, digital voting etc. But some of the areas such as the digital content distribution, social networking, etc. doesn't fit under its helm.

So what do you think about them? 

PS: This is my first post, just checking out!