I have seen a lot of 3D printers using anti backlash nuts on the Z axis and I wonder why that is a thing. Usually on Prusa3 style designs, the whole X axis rests on the lead screw nut. On "cube" style printers, the whole bed rests on these. Shouldn't the weight resting on the nuts be enough to stop backlash? It's not like the bed is rapidly moving up and down so it could "jump"?
My thoughts -- It can't hurt. If there is slop, there is more chance of vibration. Besides, it is only $1.25 more for an anti-backlash nut.