Walk into any homeware aisle and the two blur together: round brass plates, decorative, labelled interchangeably. In actual service they are distinct tools.
The puja thali is a tray. Its shallow raised rim contains things — rice, kumkum, prasad, small items that would otherwise slide. It carries the whole ritual's inventory and often serves as the working surface during puja.
The aarti plate is a lamp platform. Traditionally flatter, sometimes with a central diya holder or hanging ring, built so flame can burn securely while the plate circles before the deity. Its design question is fire safety and sight lines, not containment.
Owning one piece and doubling it works for many households — a thali with a small diya placed centrally performs aartis perfectly well for daily use. Dedicated separate pieces earn their shelf space mainly in households performing elaborate daily rituals or hosting frequent functions.
Whichever you own: keep flames on metal briefly and supervised, wash by hand after smoke exposure, dry immediately. Soot lifts easily young; it sets stubbornly old.
Flat brass aarti plate with burning diya beside a rimmed puja thali.