Why does this SwiftUI Picker code not work?

Question

Xcode: 11.2.1

The code below is for a simple form with two components; a Picker (to select a letter) and a Text (to display the selected letter). The code compiles

Answer 1

Just for the record, I'm answering my own question based on the accepted answer above and my increased knowledge as a result of that answer. In the question I was not selecting a letter from the array but the index of the letter in the array. So, based on the insight, an alternative working solution might be:

struct ContentView: View {

    @State private var letterIndex = 0
    private let letters = ["Alpha", "Bravo", "Charlie"]

    var body: some View {
        NavigationView {
            Form {
                Picker("Select a letter", selection: $letterIndex) {
                    ForEach(0..