You can use bitcoin for shopping. Here is a list of places: http://spendbitcoins.com/places/
The eco-system is still very young. And only a handful of countries, like Japan and Australia, have legalized bitcoin as legal tender. Until that day comes, and until they make it simpler to use for ordinary people, it will be some time before it is adopted in a massive way. Think Internet back in 1991.
TenX is looking to bridge the gap between cryptos and traditional banking. https://www.tenx.tech/
Cryptocoins are also used to buy illegal stuff on the Darknet (think Tor) and for money laundering (think China). Oh and don't forget hackers demanding ransom (think HBO/Game of Thrones). Governments are going to be regulating this market soon enough. Until then, it's the wild wild west.
RE: How do you use cryptocurrencies?