Replying to Ski Flex and Jibs

I've heard many people say stiff skis are great for stomping big jumps which makes sense. What doesn't make sense to me is why a soft ski would be good for skiing rails.

From my experience, stiff skis require more edge and boot pressure to flex the ski and make a good turn. They're usually better for heavier, more aggressive skiers while soft skis are easier to initiate turns on but don't stand up well to high speeds or big forces like landing a big jump.

How does this affect rails?

I would imagine a stiff ski would allow you to really grip and rip a rail and launch you off the end. Unless you were doing a bunch of nose presses I don't see why you would want a soft ski for anything other than butters.

Can someone please explain? I tried using the search bar but I'm either terrible at it, it doesn't work well, or this thread doesn't exist.