Aw yeah finally got me a basic rice cooker! Basic as in no fancy feature or functions! Yeah it comes with a steam basket, but it still works by pushing down on the lever switch and turns itself off when the water is boiled away. No timers or anything!
Legitimately fascinated with how simple the design is for those things, too. Like seriously, these things turn on and heat up to 212 degrees F (100 C,) and because water can't get any hotter than that for a variety of reasons, the heating element does not get any hotter. But as soon as the water is gone? Oops there goes the temperature climbing again! But oh wait the magnetic surface that keeps the thing on loses its magnetic properties above water's boiling point so off it goes! No burning rice
And though heat can absolutely permanently destroy a magnet, it won't ruin the cooker because the magnet can handle quite a bit hotter than 212F/100C. The magnetic surface it attaches to though? Loses its magnetic properties once it reaches beyond boiling. But once it cools off? It becomes susceptible to magnetic forces once more!
(The point at which a magnetically influenced object loses its magnetic properties is called the Curie point, BTW!