It allows removing the landing gears on the booster, which saves wheight, which saves fuel, which increases efficiency and reduces costs. It also avoid having to fetch the booster from wherever it would have landed.
Given that a lot of the landing failures we've seen started with a near perfect landing followed by the rocket tipping over, I suspect one benefit is that the contact point is now above the center of gravity and thus it can't really tip over.
Of course, it can't tip over unless something fails or the rocket ends up in the wrong spot (and fails to get caught) and the previous tip-overs also had to involve failures (of the landing strut, in the latest loss) or landing in some way that isn't perfectly aligned.