They have their place for winter riding; fat is good. I've been riding a vintage mtb with 26 x 2.1 studded tires. I wouldn't mind a wider tire when conditions get really dicey, though. I'm just surprised by how few fat bikes I see in winter. I see a lot more fat tires in good weather than bad which is a bit weird.

The price of studded tires for those things is pretty prohibitive. A lot of people ride beaters in the winter cuz their bike is going to take a beating in the winter. I know mine does.