The Auto-Jump-Feature let the player jump e.g. when you build a house and you remove 1 layer of the grass/stone to build a floor. While doing this the player often jumps on the block you are currently digging. Also the auto jump lets you jump when you're walking through a cave, its getting dangerous when youre standing on the edge of a cliff, and the player automatically jumps into it. (only if there is a higher block in front of you he jumps on it and falls into the cliff)