Reading from four separate places in the Scripture every day gives you a better grasp the unity of the Scriptures, as well as enjoying the variety of four viewpoints.
To prevent the frustration of falling behind, which most of us tend to do when following a Bible reading plan, each month of this plan gives you only twenty-five readings. Since you'll have several "free days" each month, you could set aside Sundays to either not read at all or to catch up on any reading you may have missed in the past week.