Let's look at it this way;
Airplanes use aluminum fuel lines, and sit on the ramp, out in the weather for months on end, without even being started.
They don't have any trouble with them, just the rubber hoses have a "life limit" placed on them. And must be replaced after a period of time regardless of condition. There are bends in the lines, and flared fittings. But the flare is not as flat as the flare used in the auto industry. also not a double flare.
Granted; 2024-t3 aluminum "work hardens" but there's no need to use that alloy in a car. There are softer versions such as 2024-t0 which hasn't been heat treated, and is much easier to work with.