It does not need to be Store Selection, necessarily. That's only needed, if you have a use case for the stored selection further down the line.
Otherwise the Selection node does the trick as well. In my mind, it's like initializing the default or active selection.
I'm aware, the point here was to demonstrate the named selections.
Yet, I'd like to mention, in such case it is not needed. I guess, it's always good to know options:
I already posted a feature request, that we get a dropdown button to set the predefined selection names (default, all, odd, even,...).
And, because I stumble across it, it is terribly easy to forget the quotation marks, when referencing named selections. I really hope, Maxon will find a better way. Maybe simply fall back and try if there's a named selection, if the entered string is not a predefined selection name. Or maybe the other way round, have the predefined names start with a $ or something, so that the custom named selections can be referenced directly. But in the end, that's probably only my personal preference and problem.