Ok, this is a classic example of regional preference. Here in the US, drivers are taught on the basis of threshold braking. That is, we brake in a straight line before turn-in. What this does with the higher rear spring rates is forces more weight over the front tires for more positive turn in, while allowing for a lot of rotation in the rear, until power is applied at the apex, effectively planting the rear tires again.

In Japan, trail braking rules supreme. Drivers will drive into a corner as fast as possible, hit the brakes VERY late, and stay on them until they're ready to hit the power again. By driving in such a manner, they're getting almost the same effective weight transfer that US drivers are, which means they're getting about the same handling, but their corner entry speed is usually much higher, at the expense of a little corner exit speed, which is focused on here in the US. You may also notice that drifting is also much bigger in Japan than here, and so higher front spring rates play a huge role in that, but more for the reason of guaranteeing steering control with the car sideways, while allowing the car to remain sideways; which is difficult at best with a US prepped car once you apply the power again.