DeFi allows you to do many things. Broadly speaking, there are two main aspects:

• Recreate traditional financial operations, but with the implementation of crypto.
• Create new financial instruments, based on crypto.

As you can see, it is a totally disruptive new technology.

An example that I always include:
The Spanish financial group "Santander" is one of the pioneering banks in the foray into DeFi. In 2019 they used the Ethereum platform for the liquidation of the interests of a trust bond of 20 million dollars.
Here is the link for you to learn about it:

https://cointelegraph.com/news/santander-redeems-20m-bond-using-ethereum-blockchain?_ga=2.210247893.1960222452.1593710805-1353565757.1592980920