Could you imagine a version that would splinter into hundreds of thousands of shards at about a half mile above a group of ships?
Unfortunately, a shard with, say, only a KG of mass would lose much of its kinetic energy in a half mile through low altitude atmosphere. (How much is difficult to say.) You need big chunks so that the wind resistance doesn't dissipate their energy quickly.
Still, a round could be developed along the lines you propose if the lower total kinetic energy is more than offset by the area coverage. And it wouldn't necessarily have to fragment at a half mile; maybe much closer, thus losing less total kinetic energy.
And the aiming of a single, small, hypervelocity projectile at large distances (> 100 mi) is problematic, which argues further for a fragmentation round for certain target situations.