GCN's sibling channel, GMBN, has done ride comparisons between fat bikes and full suspension bikes. While the full suspension mountain bikes usually came out ahead overall the expert riders were impressed by the versatility and user friendly rides of the fat bikes.

That in part was what motivated me to get somewhat fatter tires for my hybrid a year ago. The tires were nominally 700x40 but were actually closer to 45 wide. At 40-50 psi it was significantly easier to ride rough gravel and rutted roads than with the road oriented 700x38 tires the bike came with. And I might go even wider since there's enough clearance.

On several casual group rides this year around downtown one or two fat bike riders have joined us. No trouble keeping up with the modest 12-15 mph pace, but those guys are younger and stronger than I am. The bikes sound like Panzer tanks rolling. A lot of energy must be wasted on knobby tread on pavement. I'd guess that a chevron tread pattern like the Schwalbes or my Michelin Protek tires would be a better all around choice for a fat bike, including most off road riding.