Give us reason why do you think that? Knowing that visa is used to transfer money in the electric way and that bitcoin is itself a digital format of money well we could compare some aspects of it. Though bitcoin has a problem with scaling and with price fluctuation. Where as visa does fiat money transfers which at its core means that fiat is stable and it can process a lot more transactions.  So for bitcoin to be even seen as an alternative to visa it has to get a lot of things done.