Bitcoin is rapidly becoming a currency, the crypto world's reserve currency, playing the same role as USD (though in the latter case not for long). My take is that eventually the volatility of classic bitcoin will decrease to the point where where it will trade like a first world currency, with only fractional fluctuations. Once that's the case, even small coffee shop type transactions will settle in bitcoin. This will drive the bitcoin day traders crazy.

Bitcoin proxies such as Bcash and BCH will be more volatile than BTC, but trading around bitcoin, somewhat like the Norwegian Krona or Swiss Franc trades around the Euro.