Saving grams on a fatbike
Well it depends how many grams and where.
Wheels andtyres are probably the best place to save the grams. Going tubeless is desirable, my fat bike tubes weighed in at 550g each.
If you buy a carbon frame, Sonder Vir Fortis, you can build a very light fat bike, mine comes in at 12kg with a Lauf fork without any bling apart from the DT Swiss BR2250 wheelset.
Very comfy as well with low pressures.
I think a lot of the weight conception is still from the heavier steel framed bikes out there. But I will agree that weight is just part of the equation.