I think it is clearly both. Increasingly more high-profile businesses are already accepting or considering accepting payment in bitcoin.
It really depends on the way someone will make use of it. Oroginally, it was made to be a just a digital currency, and it still is a digital currency up to now. However, many people have used the special characteristic of cryptocurrencies as an investment due to it's potential to grow, thus leading to more profit.
Yes, for me cryptocurrency is both asset and currency because we can also use cryptocurrency to pay bills or used it to transaction accept any payments as well. But some said that cryptocurrency is a digital asset like bitcoin, they say bitcoin is more an asset than a currency.