I don't think, just too many people want to profit from the bitcoin, led to excessive bitcoi prices, but the bitcoi in the future could become international currency, so I think the bitcoi is not a bubble,
I agree because in the past the bitcoin demand was much higher so most individuals ambition was to buy more and more bitcoin so with the increase of high demand bitcoin price increased to the highest level but like in many things in the financial world anything goes up will be down some day and bitcoin did the same way but the situation is not permanent so it cannot be considered as a bubble and I think bitcoin is going through a significant time period these days to become a reputed currency in the future