Are there cases when you would want a public readonly field v.s. a get-only auto-implemented property?
public class Foo
{
public readonly string Hello;
One reason would be for data binding - .net implements binding to properties but not to public fields.
Some discussion here : Why can't we use public fields for data binding in C#?
Making it a property rather than a field means it can be used on interfaces.
The exact implementation (although auto-properties don't really have much implementation...) is also abstracted, so you could in the future base it on a combination of fields without breaking (compile) compatibility.