A short conclusion for you first:

• Now (React 16.8+) 👉 Almost all new projects: choose Hooks
• Class is mainly "historical legacy + maintenance of old code"

1. From the official and ecological reality

1️⃣ The official attitude has been very clear

• New features are only designed around Hooks

  • useState / useEffect / useTransition / useSyncExternalStore
  • Server Components、Concurrent Features

• Class is not deprecated, but will not be enhanced

• The core meaning of the original words of the React team:
• Class is the compatibility layer, Hooks is the future

2️⃣ Ecological status quo

• New library almost Only provides Hooks API

  • React Query
  • Zustand / Jotai / Redux Toolkit
  • Framer Motion

• Tutorials, Examples, Best Practices: 99% Hooks

👉 Using Class will make you break away from the mainstream ecology

2. From the perspective of "coding experience" and "maintainability"

1️⃣ Same logic, compare

Class

class Counter extends React.Component {
  state = { count: 0 }

  componentDidMount() {
    document.title = this.state.count
  }

  componentDidUpdate() {
    document.title = this.state.count
  }

  render() {
    return (
      <button onClick={() => this.setState({ count: this.state.count + 1 })}>
        {this.state.count}
      </button>
    )
  }
}

Hooks

function Counter() {
  const [count, setCount] = useState(0)

  useEffect(() => {
    document.title = count
  }, [count])

  return (
    <button onClick={() => setCount(c => c + 1)}>
      {count}
    </button>
  )
}

👉 The advantage of Hooks is not just "short", but:

• Logic aggregation by "function"
• no longer scattered across componentDidMount / Update / WillUnmount
• No this
• No need to manually bind context

2️⃣ Logic reuse: Hooks wins

Class reuse method (history)

• HOC (nested hell)
• Render Props (JSX nesting doll)

Hooks

function useTitle(title) {
  useEffect(() => {
    document.title = title
  }, [title])
}

Custom Hook = "Function Abstraction" at the logical level

This is something Class can never do.

3. From the perspective of React’s internal principles

• Fiber
• renderWithHooks
• Hooks Dispatcher
• Why can't hooks be written in conditions?

👉 This is exactly the key point.

1️⃣ Hooks and Fiber are "natively bound"

• Each Function Component corresponds to a Fiber

• Hooks exist on the linked list of Fiber.memoizedState

• renderWithHooks When rendering:

  • Set up Dispatcher (mount/update)
  • Sequential reading hooks

👉 Hooks are “first-class citizens” of React’s new architecture

2️⃣ Class is essentially “outer encapsulation”

• this.state、this.setState
• life cycle methods
• All simulated on Fiber

It can be understood as:

• Class = old API, running on new kernel
• Hooks = use the new kernel directly

4. Are there any “better” scenes in Class?

Yes, but rarely 👇

✅Suitable for using Class

1. Maintain old projects
2. The code base is already in Class style and there are no plans to refactor it.
3. Requires componentDidCatch (but now Hooks have alternatives)

❌ Situations when it is not suitable to reuse Class

• new project
• new components
• Want to learn React principles/concurrency features
• Want to follow the mainstream ecology

5. A conclusion from an engineer’s perspective

• Class is "How to use React"
• Hooks are "how to think about React"

If you are asking:

• Interview 👉 Hooks
• Actual Development 👉 Hooks
• Deep into the source code / Fiber / Scheduler 👉 Required Hooks
• Take over the old code 👉 Just understand Class, no need to write new ones