It is possible to actually have better geometry with a small block then running a higher arc spring. In short it has to do with the roll steer of the rear axle.
Blocks are used by the OEMs even though it would be easy enough to just spec a spring with a higher arc. As far as an OEM application it is simpler and cheaper to have a second part number for a taller spring instead of a set of blocks, different U-bolts, and a more complex assembly build.
But blocks are not perfect. They add leverage to the axle, allow for more axle hop. Not a good thing if you are putting enough HP to the ground to be getting into tire spin (and hop).
I have no fear of a small block. But when the block is the local parts store special, extruded aluminum, taller then it is wide, smaller then the length of the axle spring perch, those I have issues with.