Had 29er hardtail (sold it), had carbon full sus (sold it) and still have fat bike.
I think it comes down to what you ride locally or mostly, fit the bike to that in some ways but also what makes you grin.
For me the FS was good but you get complacement and lazy and it forgave you, but, the fat bike is plush to ride (once you frig the tyre pressures right), goes up and down anything (think pedal a landrover) but has its own challenges (weight, piss take from makes) but I forgive it that .. oh and it doesn’t cost me a couple hundred quid a year in servicing and pivots :/
Will you miss it? Maybe, like I sometimes miss a CX bike, never had one but miss it 😉
James