I'm like 99% sure Google said "what's the most contrived workload that technically counts as quantum supremacy" and went from there... That being said, we certainly live in interesting times.
Even if it's highly contrived, it's still something that they found a task for which the quantum computer is superior. It points the way towards a more general superiority where some at least have doubted the possibility.
I agree, I'm just pointing out that it's not useful yet