Every time I see a person on a fat bike it looks like they are riding it because they own it and not because it's ideal for conditions.
That said, I have been out on my winter bikes, really suffering, and thinking that I'd like to gear down on a fat bike. But that's my imagination wishing that six inches of chunder over ice weren't trying to take me down while getting punched in the face by a freezing ice storm, it's not like people on fat bikes are passing me.