I got to know about bitcoin fairly earlier than many people, when the price was around $500 and then shot up significantly a year back. However, refrained from investment in that as it is total gambling as there is no intrinsic value...Now it is just being bought / traded due to the way it has shot up every month in 2017. Don't know why our beloved Islamic scholors - who are quick to judge everything haraam, are silent on this as clearly this bitcoin investment is based on pure speculation.
Even if we compare it with other speculative investments, like stock or real estate, at least a share of OGDC or a plot in DHA has some intrinsic value - i.e share of a stock represents your ownership in the firm and you get dividends from company's annual profits. Similarly prices of DHA plot may shoot up due to speculative activity, however one can still live in the plot or rent it even if with no speculation in price. However you cannot justify why 1 bitcoin is equal to $20,000. It is all just in the air and that's what gambling is all about. One golden rule in investment is never invest in something you don't know.