Regarding Log Cabins, why are the vertical surfaces made flat?

Question

It seems to me that making the wall surfaces flat was a great deal of work for not much return. One could argue that this made the interior walls nicer, but what would be the advantage of making the exterior walls flat?

Answer 1

On the outside it helps shed the rain better. But I like the traditional look best. Inside the flat profile is more convenient for attaching things like cabinets and partition walls.