Everyone would like the bitcoin is accepted in all online and real stores and, as as mentioned in the title, what would happen if Bitcoin became a legal currency?
Bitcoin is not legal in many country. If it is legal in its own present term and conditions then the price of a country own currency will be fall. Their will be a possibility of economic crisis in those countries. The tax collection will be decrease 
. And this thing seriously affect an country economy growth. And i think their will be a possibility of increase in crime rate. And this is because the uninterrupted and untraceable money transaction facility given by Bitcoin. And if Bitcoin is legal according to government term and conditions then the price of Bitcoin will be stable. And it will be a simple currency like others. 