I'm having a good time on my fat bike, not sure I'd want it as my only bike though. I previously used a hybrid as a winter bike, and just left the studded tires on it for that purpose. Still, there is a lot of time, that those lovely Gravdals can't get me out my 1/2 mile long driveway because of the blowing snow across it. And, there are a ton of fat bike rides that I was missing out on
So, the fat bike allows me to continue riding local gravel like I had intended the hybrid to do, and unlike any of my other bikes, I can actually use the groomed atv/snowmobile/bike path that starts only a couple miles from my door, or the groomed fat bike trails just a half hour away. I can see getting some really nice rolling summer weight fat tires if I still want to hit the trails during the summer as a break from my usual road rides though, and it's a heck of a good workout, but in an enjoyable way, at least to me.