in fact it a digital cash that we have to use for online shopping and online business etc. but currently as people are using it as investment and for trading purposes therefore if we call it as digital gold it may not be wrong. in fact most of the people still cannot use bitcoin as currency and therefore they are changing it into fiat if they need it and want to use it, bu still to me as we are already using bitcoin for online purposes and hope that very soon we will become able to use in local shops also, as they still need to convince about the acceptance of bitcoin.