The confetti fires from wherever you click, arcs up, then tumbles and fades under gravity — a one-shot celebration for the order-placed / added-to-cart moment. It settles to nothing on its own, so the phone does zero work once it lands.
Capability-light one-shot. No burst is running until you click; the canvas loop self-terminates the frame the last particle dies, so idle / off-screen / tab-hidden cost 0 rAF. On a phone the count is trimmed (lighter, still runs). Under reduced-motion the burst never fires and every button behaves exactly as authored.