DeFi enables any two parties to securely and directly transact without involving an intermediary or central authority. The result is that many more people can access financial services at lower costs or receive better interest rates than those offered by traditional financial institutions.
I would argue your statement is not entirely correct.
To clarify - Enabling any two parties to securely and directly transact without an intermediary is a trait of the blockchain itself.
What defines DeFi is the reinvention of all those financial instruments the old money system has - borrowing and lending, coverage and insurance, leverage, arbitrage, exchanges... but also new ones, like staking. It's important to underline, that these are not exact copies of TradFi, but reinvented crypto-native iterations of these tools, while staking doesn't exist and is not possible in TradFi.
More importantly, lower costs and better interest rates are not at all given in DeFi! Nothing makes it impossible to be worse, it's merely incentivized to be better. But this can easily get worse than TradFi if a DeFi protocol goes out of balance. E.g., DeFi on Ethereum is hell of a lot more expensive because of the gas fees, compared to a TradFi network like VISA.
So, lower costs (depending on the blockchain, mind you) and better interest rates are just a side effect from the annihilation of centralized intermediaries, which is the main purpose of DeFi.
By decetralizing finance, the blockchain destroys corruption and control. It's that simple
Hence "financial freedom" - it doesn't mean getting ultra-rich and fast... it means you are free to do financial conduct without any authority's supervision or mediation.