When I say flexibility, what I mean is how many different conditions it's appropriate for. Hot and cold. It makes sense about the wicking though, because even if you're wearing a separate wicking shirt under the rain jacket, the liner makes much better contact with the outer shell than your base layer. I suppose if you got too hot, you could strip off your base layer and just use the jacket by itself. No one wants to change in the rain though, and there may be modesty concerns depending on where you are, who you are, and who you're with.
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The journey is more important than the destination.