I await more interpretations of this ruling while wondering if this nullifies Puerto Ricans’ ability to vote in any U.S. election.
PR vote in presidential primaries but have no electoral votes to vote for president. They have a non voting delegate in Congress.
What it does do is remind everyone that the "Commonwealth" government of Puerto Rico is a creation of the US Congress, which has the legal authority to override its control of the island's finances.
Of course that also means that the Fed Gov may be on the hook for any debts incurred by the "Commonwealth", just as though the DOD or Interior borrowed money and failed to repay it.