One Piece: What's the Use of an Encyclopedia System?

The protagonist transmigrates into the world of One Piece and gets an Encyclopedia System from the start. He thinks it will be useless, but soon finds himself relying on it at every turn. It turns out to be a real lifesaver. This is the story of an ordinary man who, after gaining a System, wants to go home but can’t bear to give up the power he has found in the world of One Piece.