Many people think that Bitcoin is like a bubble, so its price goes up rapidly to its peak and will plummet.
I do not think so. Bitcoin was born in 2008 but until 2013 new Bitcoins prices have increased to a few dollars per BTC and up to 2.3 years recently new BTC prices increased several hundred dollars a BTC. This route is too long to see the BTC as a "bubble" with its advantages.
Bitcoins are currencies as well as euros or dollars. They are only valid when dealing, buying goods through technology. If people do not accept do not want to use for trading, it does not have any value. What do you think if one day people do not want to use euro or dollar but want to use Bitcoin to buy goods? Bitcoin will rise in price, but will the euro or dollar fall?