Just a simple opinon on why bitcoins are not so dangerous. Bitocoin is like a giant decentrialized paypal. its secure, its accepted as online payment, and it can be converted back and forth between cash. however there are differences. Bitcoin is not regulated, its even more private than Paypal, and its not a buisness.
 the main reason Bitcoin shouldnt fail is because there is money put into the system by people buying things with bitcoins, and buying bitcoins with cash. most people dont want to lose money, so they wont sell bitcoins below a certain price, and as more buisnesses accpet bitcoin, the currencys lowest price will go up due to the value of the products you can buy with bitcoin.

so as long as buisnesses accept bitcoin, and dont accept lower prices, than the price should remain stable.