An important point about the technical meaning of "quantum supremacy": It is only the claim that a problem exists that can be solved on existing quantum computers and not on existing classical computers. The problem that Google used to demonstrate quantum supremacy has no practical uses, and no useful problem is known that can act as a witness for quantum supremacy. The practical implication: "Getting you problem solved" cannot be the motivation for buying quantum compute power from D-wave (unless you have no clue). Possible valid motations: "learning to work with quantum computers", "seeming cool", "donating money to companies that may build useful quantum computers in the future".