Quantum supremacy means quantum computers are now better than classical

Quantum supremacy (now often called quantum advantage) means a quantum device completed one specific task faster than the best known classical algorithm for that task. The task — random circuit sampling — has no known practical application. It was specifically designed to be hard for classical computers and easy for quantum ones. Classical supercomputers have since improved their simulation algorithms and reduced the estimated classical runtime dramatically. Supremacy for one contrived task does not mean quantum computers are generally better.

Random circuit sampling requires hundreds of qubits to demonstrate — beyond browser simulation. The key lesson is about interpreting benchmark claims, not about circuit construction.