I really don't think the cable is limited to 2.4A. Instead, since it is USB-A on one end, instead, I believe it is that the USB-A quick chargers are all limited to 2.4A, so they are merely stating they will do the max voltage that a USB-A Quick Charger will provide. I suspect that any chargers made with a 3.0A connector will have a USB-C type connector (such as the Google charger), so even if this cable is limited to 2.4A (which I don't believe it is) it is likely not to matter.
As for being 480 Mbps, that doesn't matter for the 5X or 6P, as both phones only support the USB 2.0 standard.