Bitcoin, in contrast to the euro or others currencies has no legal price, that it. No one is required to accept it as payment. Today mainly
the sites about online games, sale of computer equipment and Internet services, such as the host of World Press blogs accept it and it is still just a fews.. But it fulfills the three economic functions of money: Unit of account, it allows to measure the values (prices in bitcoins, on). Some e-commerce sites ntermediate trade, it allows to set the transactions; store of value, it can be stored (on a digital portfolio hosted on a computer, a tablet or a smartphone) for a future purchase.
Store of value doesn't mean whether or not the medium can be stored, it means that the medium itself (bitcoin in this case) stores the value assigned to it. This is the test that bitcoin fails. Storing value necessitates price stability. If you look at all failing currencies, none of them were literally worthless, they all had some value, so they were technically a store of value. But they were useless as a currency because there was no price stability. Dead currencies suffered under rapid inflation. Bitcoin doesn't have a one-way only trajectory; it swings in both directions, but the price movements make it just as useless as a currency, because you can't be reasonably certain that the value you put into it today will be the same in a week, let alone for the long periods of time that are required to have financial security.