I'm wondering why bitcoin was made if there are too many currencies in each country, why would anyone add or make a type of currency in the internet? For easier and faster transactions or so ?
Well if we look into bitcoin, the main purpose of bitcoin maker with bitcoin are :
1. Decentralizing the economic power from the central power.
2. More privacy on transaction as every transaction are anonymous.
3. Total amount of bitcoin can not be increased.
I don't know how you categorized it as dangerous. If you mean it by the way how it is used, like criminal things, remember that the real money (fiat) also used in criminal things way before bitcoin comes.