If it walks like a duck and quacks like a duck, it must be a duck. Justin Sun, the founder of Tron, is a well-known copycat that plagiarized the Ethereum whitepaper word for word. It appears he is borrowing UST’s playbook by mirroring Terra's way of maintaining UST stablecoin’s peg with the blockchain’s native token, LUNA.
The Tron DAO, which stands at $2 billion with a goal of raising $10 billion, is similar to the Luna Foundation Guard's reserve that supports the UST's peg. And the "risk-free" 30 percent annual yield is a method to generate demand for USDD, just as Anchor, a Terra blockchain savings and lending protocol, boosted demand for Terra's stablecoin with a 20 percent annual yield on deposits in UST.
Once a copycat, always a copycat.