Two-way data binding trades a slightly more complex and less transparent rendering model for more efficient rendering. You don't re-render the entire component

Two-way data binding trades a slightly more complex and less transparent rendering model for more efficient rendering. You don't re-render the entire component and diff the two components you have to understand changes, you simply change the leaf. I'd say in Vue it rarely causes troubles, in React world it leads to few non-obvious edge cases where React's one way data flow is indeed easier to reason about (but less performant).