Weight savings is the correct answer. Jacking the nose up high was for weight transfer, and therefore, traction. Willys was popular because they were far, far, lighter than say, a '40 Ford. I understand a '40 Willys only weighed about 2400 Lbs. That is light. It's also why you would see, for instance, a '40 Willys with a 392 hemi in it running A/GS, but a '40 Ford with that same 392 hemi in it might be in B- or C /GS, because back then most classes were defined by cubic in to weight ratio. Heavier car with the same engine- ran a lower class. Lot's of guys running the bigger cars, like tri five chevis, would figure to save weight by running a straight axle over an independant front suspension, which might be true if they used a lightweight tubular racing axle. But many just grabbed whatever truck or old car forged "I" beam axle, and as often as not, it weighed as much as the independant suspension.