Do we really need bitcoin?
Of course we need bitcoin, who doesn't? Although the importance depends on the user, in some parts of the world where there's no restrictions on the use of bitcoin it is been used for payment purposes, why some use it as a form of investment, imagine buying it at $300+ when it dipped earlier this year and selling it at the current price right now which is $13,000+ and its still showing no sign of slowing down, it is undoubtedly one of the best investment one can make nowadays,
just buy more bitcoin 
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OP asked if we need Bitcoin maybe referring to it as a mode of payment since there are many other cryptocurrencies existing in the world market. Investing into it is really profitable but given the market volatility which is in its nature, there's huge risk of losing since things are uncertain in this market. Anytime, its market price could go down along with your investments resulting to temporary loss. Earning profit from this technology is not as easy as it sounds because deep market analysis is needed for such thing to be earned.