In days of really crappy powder, that might have been a consideration. By the 1850's, the Brits were making rifles and smoothbores with 24" to 30" barrels & these worked just fine.
Prior to 1820 or so, powder was not very good and longer barrels might have been a direct advantage due to that.
Today, for chunk, bench and plank guns, weight and sight radius are the deciding factors.
Concerning rifle weight for offhand shooting, Harry Pope wrote that "a man's rifle should
weigh 14 to 16 pounds and a woman's rifle should weigh 12 pounds complete". These, of course,
were equipped with hooks for the arm pit, palm rests for the hand.