Hi MaCritic,
We understand you have questions about the magnets in iPad. We're happy to offer some guidance.
The magnets on iPad are used to attach it to accessories like cases and keyboards. Here's examples of ones Apple makes:
Smart Folio
Magic Keyboard
The cases have magnets in them as well that align with the array of magnets on the back of iPad to create a stronger attachment when they're connected. The magnets are not really designed to attach the iPad to a surface, like a refrigerator for example. If you are attaching the iPad directly to some metal surface, just be sure that it is attached well enough that it won't fall. If the iPad falls on to a hard surface you run the risk of damaging the housing or the display glass.
Hope this helps. Cheers!