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.
so far no, the banking system sees crypto as a threat problem many countries don't legalize crypto that's why banks won't cooperate with crypto. Traditional banks can provide many types of loans, houses, cars, installments etc. defi is a type of crypto-based loan and it will never threaten conventional banks. I think this is a simple explanation
Banks still in doubt about where the crypto will proceed,
even there are some countries that open with adopting crypto the banking business still not in the process of fully adopting this system.
Like how you provide your example, there are deals that banking can offer, but unlike with how defi works,
banks are more likely to a secure side that they are always in control.