right now bitcoin is still be considered as new gold in internet than currency, bitcoin is still has problem with block size and
it is not suitable be used for payment transaction method.
bitcoin more than suitable used as payment processor ,
it has fast transaction , most secure payment method , low fee and easy to use ,
and online transaction actually the market target .
What is your reference before saying bitcoin is fast transaction? Waiting till one day and not confirm is not fast mate. How you can pay your bill and leave the restaurant where you eat if the transactiong being delayed? Its not fast at all.
And you said its low fee. Do you think send $100 worth in bitcoin and pay $15 till $25 is low fee? I dont think so.