Since there's no rocket in existence (as far as we know) that uses it for launching payloads it's revolutionary. Rockets are so large because they need enormous

Since there's no rocket in existence (as far as we know) that uses it for launching payloads it's revolutionary. Rockets are so large because they need enormous amounts of fuel to fulfill their mission. Making rocket engines more efficient cuts down on the fuel usage and reduces their size, or alternatively, increases mission flexibility.