What the phrase covers
Decision rights define, for a given decision or category of decisions, who provides input, who recommends, who approves, who can block, and who is accountable for the outcome. Frameworks such as RACI and DACI exist to make the allocation explicit; the substance is the allocation itself, not the acronym used to record it.
Speed, quality and the cost of ambiguity
When rights are unclear, organisations do not stop deciding; they decide slowly, repeatedly and defensively. Proposals tour the building collecting endorsements because nobody is sure whose endorsement suffices. Decisions get made, then remade when someone senior discovers they were not consulted. And the most corrosive pattern: everyone assumes someone more senior owns the call, so a decision that matters to five functions belongs, in practice, to none of them. Before any major commitment, the preparation question is blunt: can everyone in the room name the single person whose yes makes this happen, and would that person agree?