A cultipacker does so much more than just pushing seeds in. One, it firms the seed bed prior to broadcasting small seeds. With firming the seedbed, it will also close up many voids where the small seeds can fall in deeper and then not be able to germinate and reach the surface. Packing the seedbed will also help conserve moisture. The V shaped pattern left by a cultipacker will also keep moisture in the bottoms of the Vs and provide some limited protection against runoff.