Pro
Efficiency reduces waste, extends resources, and frees human capacity for higher pursuits. An inefficient system consumes more than it produces, harming everyone who depends on it. Optimization is care at scale.
cf. Mill, Utilitarianism
Con
Efficiency as a primary value eliminates redundancy, resilience, and the slack in which creativity, rest, and human dignity reside. The most efficient system is one that treats people as inputs. Efficiency must serve values, not replace them.
cf. Havel, 1978