If the Pyramids were gone, it would be much easier for Israel to nuke Cairo. Just saying.
Unless it were a direct hit, even a thermonuclear weapon wouldn't do much to a pyramid .... maybe give it a nice green frosting on one side.
The Izzies could take out Cairo and environs with a 25-megaton weapon and not bother the Pyramids in the least, as long as Ground Zero was far enough away to keep blast overpressures under what is necessary to fracture the Nummulites limestone the Pyramids are built of.