Because of the long confirmation time and transaction fee of BTC I doubt if it will gain that adoption of using it as payment, BTC itself is rather a store of value and other alts that complement BTC can be used for payment.
Indeed, in past few weeks many bitcoin user complaining about long confirmation transaction. Its take more than 7 hours my transaction complete. I am believe bitcoin will be store of value and long term investment rather than currency. I am more comfort using bitcoin if bitcoin regulated by government