i think the big deal is if u have been following elon musk,man has launched many rockets since the 1950s to space delivering payloads or space shuttles but the rockets are jettisoned after flight and never recovered,making them one use only and very expensive.
elon musk has successfully launched a rocket to outer space and reentering the atmosphere,and maneuvering it to land back safely on the launchpad,making it the first rocket in the world with infinite reusability and the cost of launching it limited to the cost of the fuel which is less than 2 percent of the construction of a rocket.these allows hundreds of trips from earth to space using the same rocket and the first step to human space travel.