[Bruno]

Extra arms is one of my favorite advantages. I don't often get excuses to take it, but I'm about to start a new campaign with a mutated Minotaur with four arms (and Ambidexterity).
He'll be simultaneously wielding a kusarigama (of a sort), a shield, and either a harpoon or a hand free for grappling/wrangling the kusarigama, so definitely making use of them.

You can probably argue some kind of bonus to a few athletic activities (most notably Climbing skill) when you have all the arms being in play, but that's not an explicit benefit. In its absence, extra arms let you (e.g.) row a boat into arrow fire while hiding under a shield, or climb a rope with a weapon and shield ready.