I'll rephrase it.
Digital currencies now are in success so what makes you think it won't?

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I think that it is because there are still some people out there that still doubt the authenticity and legitimacy of cryptocurrency. Plus, there are countries out there that has not even heard of bitcoin or cryptocurrency, let alone the blockchain technology, so we could not say the extent of the success of this digital currency. That said, to countries where cryptocurrency is legal, it is pretty successful. There are still who do not believe in cryptocurrency, but I like to think that it is getting there despite the market status.