Yes, ripple is a completely centralized coin, and for this it was subjected to merciless criticism in the early years of its existence. But, apparently, such cryptocurrencies have the right to circulate. Now there are already many cryptocurrencies with varying degrees of centralization. When choosing to invest, this, of course, must be taken into account.
But ripple is not controlled by banks. Some banks use the ripple network to improve the quality of their transactions. In some countries, due to the fact that this coin is relatively cheap, transactions are fast, and transaction fees are low, it has the highest volume as a means of payment.