It was more the convenience of being able to suction cup something to the back of the car rather than the roof, and have the bike vertical rather than side-on, if I have to fit the roof bars (bolt on rather than rails), it’s already been more faff than I’m after. Plus lofting a bike upside down on the roof?, I’m almost certain to put a dent in it and/or my back out…
Front wheel off wasn’t the preferred solution, hence my interest in the Hornet, but I think I can live with the option I’ve managed to get for relatively little (assuming it’s half decent when it arrives);
4 cup Fork mount near the rear edge of the roof, with the rear wheel resting on the boot lid, should work I think…