Therefore the win here is that they have verified that a 50 qubit quantum computer "works" (success rate > 10^-3 > 0.) No classical computer could verify a 100 qubit quantum computer in the same way (but you could verify various 50 qubit subsections of the 100 qubit quantum computer). Alternatively, if they had two such 50 qubit devices (and presumably they will soon) they can verify the second one with the first much quicker than they can verify the first with a classical computer, so in that sense the quantum computer beats a classical computer at some task.