I dont think bitcoin is a bubble or if it a bubble then it is a bubble which could not be burst ever because bitcoin is a resource an asset which could not be exhausted ever if it is used wisely moreover bitcoin is very sustainable crypto currency and it is volatile currency and the reason being why millions of people are the users of bitcoin and find bitcoin that much trust worthy because bitcoin has that potential that it can provide employment to millions and made people independent that at least they can earn their livelihood by their own.