A pyramid is connected to the Sun, it is the tomb of a son of Ra, it is protected by Atum. The main Sun temple in Egypt is the one at Heliopolis, and while it's precise dimensions are unknown, and they changed over time, it was a very large temple complex, close to Karnak in size, though I'm sure it was smaller in the OK. The axis of the gizamids do not converge on exactly the same spot, but, like the temple of Amunhotep II, are in the region of the obelisk of Senusret I at Heliopolis. Clearly this comes long after the construction of Giza, though before Amunhotep II, that obelisk is thought to be one of a pair that framed the entrance to the temple, their normal practice, and that frontage would have been very large. But the Giza monuments don't have to line up with that one obleisk, just the temple at some point. But really it's just the fact that here we have a real alignment that fits with religious beliefs, that Son of Ra thing, when before the were "only" the Living Horus, and still were. The PT join the pyramids to Atum and the Benben at Heliopolis. So we have written evidence of a link, which is far more than pyramidology gives us. So when you say this "alleged line", and Bauval does not say it does not exist, and you can check on maps yourself, it is a real line to a real place, not one of many dots in the night sky.