I just recently learned about the distinction between paucal and plural forms in my native Serbo-Croatian.
Designating groups of counted nouns as smaller or larger than five adds complexity to the language without seemingly giving much in return.
This level of precision may seem exciting to a speaker of a language that distinguishes between the single and plural forms only, but in practical use I don't see much value in knowing whether there are two to four instances of something or five to infinity instances of the same thing.
What was the practical societal context that originated the paucal form? Where does the seemingly arbitrary limit of four come from?