The only way to calculate the value of Bitcoin is by supply+demand - like for the vast majority of other commodities. In this moment the demand driven by the hope for the price to be higher exceeds by a lot the demand of Bitcoin for other uses (including investment, Darknet purchase, international transfers of value, etc.).
sorry but how hope for price to be higher is different than investment? and yet you those two are putting in opposite camps? people are buying bitcoin treating it as investment and because others are closing its investment the price goes lower so how is that a bubble? to me its normal behaviour of unregulated stock and not a bubble.