Some countries treat it as an asset, some as a foreign currency. FOr example as far as I remember, spain treats it as a foreign currency which means there is no VAT to pay, but in US you would need to pay VAT.
this could potentially point to some problem if i want to use srvice that are in another place and sell bitcoin to them, and then they use those to buy thing locally, on they country, like for example if i use a service that pay for me in bitcoin, but they are from spain, and i'm from USA
it could cause some taxes issues...