Well, already Expedia, Overstock.com, Subway, and hundreds of other stores are accepting Bitcoin as a ​form of payment both in stores and online.
As more and more companies/people get fed up with the banks telling them what they can and can't do with their own money, more and more people will go to cryptocurrencies.

Having to wait days for their money to become available, charging you a ridiculous ​$$ amount in processing fees and tons of other inconvenient hassles of having to rely on the banks to manage everything is just a few reasons people will wake up quickly when they start hearing more and more about cryptocurrencies.

Lastly, peolple don't have much faith in their owns country currency anymore and are fearful that it won't be worth what it once was​ soon.