Can anyone tell me what the deal is with mineral make up?

[pecanpie]

I don't really know what to add to my question!! Everyone seems to be doing it at the moment, whether loose or baked - apparently MAC mineralize is baked in a chocolate factory (random fact from the excellent lady in the Covent Garden store who despite the upsell to a couple of mineral products has provided me with an excellent make up bag makeover). I'm really pleased with the mineral products I've bought so far, but don't understand what is more special about them than the non-mineral products I've bought from the same brand, other than the marketing.