You're right it doesn't have as much movement as a coil spring. So, it takes very little movement to reach a higher poundage than a coil spring. With that in mind. Put a preload on the leaf spring, and you have much more poundage at the end of the hammers travel than the coil spring.
Which is why leaf springs are stiff riding on cars/trucks. Jeep Wranglers used to have leaf springs F&R and they rode hard and didn't have any travel in the suspension. In 97 they switched to coil springs. The ride was much better, and offroad they have much more articulation in the suspension.