In the beginning, BTC could be used to exchange of low value of virtual items, such as buying web sites or game points, virtual items, etc., afterwards, some people in order to get these virtual items, items may be in online auction own reality for BTC, others want to buy the real goods, but no BTC at hand, and then use real money to exchange BTC, as a result, BTC begin to flow, and have a "value".
In other words, bitcoin is inherently valuable as a means of payment; If it loses its function as a means of payment, it becomes worthless.
The value of money: it exists because of payment.
If bitcoin is not a currency, why some merchants in different country they accepted bitcoin as their mode of payment also crypto/altcoins, like fast food, restaurant, and more, then some also accepted it in online shop such Amazon, then why Japan, Korea make bitcoin became regulated and legalized it. Therefore, on this way it shows it has potentials and capacity to become like that in the near future.