People use C because it /feels/ faster. Like, if you build a catapult strong enough that it can hurl a bathtub with someone crouching inside it from London to New York, it will feel /very/ fast both on take-off and landing, and probably durng the ride, too, while a comfortable seat in business class on a transatlantic airliner would probably take less time (except for getting to and from the actual plane, of course, what with all the “security"ยน) but you would not /feel/ the speed nearly as much.