The S line of lenses are far more robust in construction, and are weather sealed. I consider the 24-70 F4 I got as a bundle with my Z5 a real bargain for the quality of the lens and price paid. Since this new lens is Nikon branded and has an additional stop, many will consider it to be a more attractive purchase than the slower F4 24-70 or the twice as expensive F2.8 24-70.
I don't see the 24-70 F4 offered as a bundle deal with the Z5 anymore, which is a shame, but probably makes more fiscal sense to Nikon. I wonder if they will discontinue the F4.