Extending an interface ensures that all function signatures are correct, and catches mistakes introduced (e.g. through errant keystrokes)
There is 1 instance of this issue:
https://github.com/code-423n4/2022-05-rubicon/blob/8c312a63a91193c6a192a9aab44ff980fbfd7741/contracts/rubiconPools/BathToken.sol#L387
