Banks don't need any cryptocurrencies, and of course Ripple, but other merchants use Ripple, such as supermarkets, small grocery stores, which I think is enough for Ripple to develop well.
Wait, but there are a lot of different projects on the cryptocurrency market, why are we talking only about the XRP project? I think that it is here that the banking sector is of real importance, and it is the bankers who are raising this project.