It was a difficult ride home yesterday. The temperature was mild (-5C/23F), the snow on the paths was sloppy and thick and my studded, deep-tread winter tires were able to catch one layer of snow but slid on layers underneath. I ended up walking about 1/3 of the 4km/2.5mi route home. I don't know if a fat bike would have done much better, probably a bit better though, my tires are 47mm whereas 4" fatbike tires are 100mm and 4.8" are 120mm so there is a significant difference in width.