Using {...state} instead of state in persistReducer in redux

So I was using redux-persist in my react-native app to persist the state and everything is working fine.

For the reducer, I was using switch-case to check for different action-types, and for the default, I was returning the state.

initialState = {
  first: null,
  second: null,
};

export default myReducer = (state = initialState, action) => {
  switch (action.type) {
    case ...:
            ... // Handling some cases which work fine
    default:
      return state;
  }
};

This thing is working fine but if I replace state with {...state} in the default block, it doesn't persist the state.

Now how much I had understood is state = {...state} so why is this not working.

Here is the persistConfig;

import AsyncStorage from "@react-native-async-storage/async-storage";
const persistConfig = {
  key: "root",
  storage: AsyncStorage,
};

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