Roselia puppets are from another age. Though beautifully carved they are very large and heavy. But in their day they needed to be large playing, on occasion to huge crowds.
Large heads necessitate longer arms, longer than a puppeteers thumb or finger, and therefore extentions are required. Unfortunately this does make for semaphore gestures, but that is a price you pay for having very large puppets. They are not necessary for today's general performing conditions.
But you are, of course, at liberty to make your puppets as stiff as you like. Most of us go for flexibility.
Do you think that moving the arms(fingers) of the puppet helps the performance of the puppets in any way?
What a very peculiar thing to ask?
There is a range of beautifully designed fabric puppets made by The Puppet Company. Folkmanis make similarly fabulous looking puppets. Most of them are pretty useless for professional work because they are padded and stiffened to make them look good. It's as you say, "it makes for a good costume" -but unfortunately it also makes for a less responsive puppet. It's the difference between ornamental toys and puppets that work.