It will be useful to protect important areas such as: houses and own buildings; and to prevent the vandalism of hostile mobs.Their spawn eggs are very easy to craft, because they need few resources that can be obtained even when you have just started your survival game.You can use it to collect resources automatically, simply by placing the "Extermobinator" of your choice in the area you want, it will do all the "dirty work" with the hostile mobs[Instant kill]; you only have to collect the items that have been stored inside.