Bubble or not?
You know everything depends on perception and what you see about the unfolding events. For those who are arguing that bitcoin is a bubble, they have their own points and even valid because they have evidence of events to support their position. For those who also hold the position that its not, they also have their reasons and I am one of those who hold that believe as well.
Bitcoin is an evolving technology that every developer and even giants in the financial world are yet to understand the mystery behind it which is penetrating gradually and that is why the volatility is kind of high but gradually it will subside and everyone will see the true potential of bitcoin.