No one can predict what exactly will happen in the future. In the event of a nuclear war, they can turn off electricity and the Internet, no currency will have value.
That is so true, and thats why i own a safe at home stocked with gold, silver and canned food haha!
Diversify, never believe in just one thing as nobody can ever now 
Bitcoin can be called a bubble, because its price will depend on acceptance. It's now worth more than it should be because people believe in it, but it all could change within weeks.