DeFi or decentralized finance can threaten the world of traditional banking, because of the shift in lending, even DeFi itself is known to be able to provide loans like other traditional banks.
This can affect existing traditional banks, because there will be competition between traditional banks and crypto in general, regardless of the various problems that will occur, crypto and traditional banks must be able to adapt to each other.
Crypto development is progressing so rapidly, this can be seen from the many users who join here, if Traditional Banks close themselves it is not impossible to be abandoned in the next few years.
Although currently crypto is still very risky, it is not impossible that in the future crypto can change finances, just need to wait for regulations or legal regulations, if this happens, it is certain that crypto will grow and be accepted by many people.
Its always good to see traditional banks to cooperate with crypto in the future. But for now, i don't see any possibilities that crypto will be accepted by the traditional banks as they even see it as a threat. And once bitcoin will be integrated in the banks transactions, that will no longer be decentralized. The thing that may totally lost the decentralization nature of bitcoin once the government decides to adopt it legally and accepted it in the banks as everything will be traceable by the government just like what fiat system is all about.