Here are four good reasons why I don't think Bitcoin is a bubble.
The power of bitcoin rests in its decentralized nature. Because bitcoin is not owned by any decentralized banking system (unlike national currencies), the value cannot be arbitrarily manipulated by currency production (i.e. the devaluation of the German Mark, post-WWII). This gives bitcoin the stability of a commodity like gold.
The supply of bitcoin, unlike all other items of value like gold or currency, is strictly limited. There will never be more than 21 million Bitcoins ever mined. The market is at 80% of that number, and will never exceed it. Mining bitcoins is only getting harder, and the value of each coin will continue to increase.
Decentralization and encryption mean that Bitcoin is secure. It cannot be manipulated by external forces and can not be confiscated, apart from the hard copy key, which is held only by the individual user entity.
Because all bitcoin transactions are recorded in the Blockchain, the opportunity for fraud is minuscule at best, and immediately traceable.
With unsurpassed security, zero external manipulation, and a limited supply, there is no reason bitcoin is a bubble.
(People were saying the same thing when Bitcoin broke $1,000, "it's over-priced" or "its shady and a bubble" well the people who saw the direction of the blockchain and held there coins are taking very nice profits or continue to hold, theirs a lot of volume in crypto-currencies if you don't know about them you should look into them they are the "Next big thing" in my opinion)
If you think that it's a bubble read and understand it before you think it's a bad thing for the "dark-net"
Investing into BTC ETH & LTC is not a bad idea to look into