Doubt about where to declare variable

Question

I have a query on an object that is in a functional component in React Native. I have created a main matrix (arrayholder) to store all data while filter the information in the status variable (clients).

My question is this, when I declare arrayholder outside the scope of the function it is filled with the data correctly, but when I declare within the scope it simply does not receive the data leaving an empty array. Why? Until then I did not understand very well the difference of declaring variables inside or outside the scope of the functional component.

Follows the code:

import React, { useState, useEffect } from 'react'

let arrayholder = [] - quando declarada aqui fora é alimentada no loadClients

export default props => {
    const [clients, setClients] = useState([])
    const [isLoading, setIsLoading] = useState(false)
    const [search, setSearch] = useState(null)
    //let arrayholder = [] - quando declarada aqui dentro não é alimentada no loadClients

    useEffect(() => loadClients(), [])

    const loadClients = async () => {
        try {
            setIsLoading(true)
            const res = await axios.get(`${serverClients}?auth=${props.token}`)
            setClients(res.data)
            arrayholder = res.data //alimento aqui
            setIsLoading(false)
        } catch (e) {
            showError(e)
        }
    }

    const updateSearch = search => {
        console.warn(arrayholder) //visualizo o conteudo
    }
}