I use my to snag eggs from the Wyvern Cove in Ragnorak.They are fairly good swimmers and amazing at climbing up to the nests. Also having the ability to wield guns while hanging from a cliff or ceiling is invaluable.
You can breed them while they are mounted on the wall. I found it's the best way to breed them because they don't move around. But be carefully their egg goes to the other side of the wall so make sure you have access to both sides.