The DeFi protocol distributes tokens to their users, and has sparked a frenzy of "liquid mining". Take the most famous liquid mining project as an example: Compound Finance. They send the protocol token to their depositors and borrowers. Compound Finance said that this is for more decentralized governance, and they hope to empower people who frequently use the protocol.
Liquidity providers can choose between migrating to the new system or staying in the old system. If possible, the new version will be backward compatible and be able to trade ERC20-to-ERC20 with the old version, similar to a custom pool.