I'm a bit surprised about the fact that the somewhat related magnetic stirrer [1] never made it in to mainstream kitchens. I used these a lot during my PhD, and can imagine them being handy in the kitchen. I suppose one difference is that in the kitchen, liquids tend to be more viscous.

As I write this I realise that popping a small inedible magnetic bean in to food while cooking is a bit of a safety hazard, so that is probably why we don't see this at home. Although, you could have larger stirring beans, or other shapes, which wouldn't be a choking hazard. -- [1] https://en.wikipedia.org/wiki/Magnetic_stirrer