In simple functions is ‘const’ or ‘let’ or ‘var’ even necessary

This is a Postman global function, but it’s what I have for an example. I have many of these types of examples in my code.

endpointUtils = {
    validateResponse: pm => {
        const responseData = pm.response.json();

        pm.test("Response field 'status' equals 'S'", () => {
            pm.expect(responseData.status).to.eql('S')
        })
    }
}

As matter of habit I define variables like ‘responseData’ with ‘const’. I’m wondering in this circumstance if any modifier is necessary, be it ‘const’, ‘let’, or ‘var’. Would nothing do just as well? It would greatly simplify the clutter in these few line functions. Am curious if this is violating some best practices at some level. Within the scope of the function ‘validateResponse’, does it really matter?