The single barrel shotgun brings a lot to the table. Having no complex reciprocating action to load and unload shells as with pump and semi-auto guns, it has both fewer parts to break, and offers a shorter receiver. This makes for a more inexpensive gun, that is lighter, has a shorter overall length, and is easier to make, clean, replace the occasional broken part, and maintain. Beyond that, you can teach a new shotgunner how to load, reload, and unload a single shot break action gun in a morning before the dew burns off the grass. Even though it’s a nearly 150-year old basic design, they are safe and easy to carry to and from the field or range, their action broken open to be visibly 100% sure they are unloaded.