Well i don't buy that raceway thingie, but a cageless bearing is better than the caged one in terms of wear and load factor, but stands worse at maximum speed rating and rolling resistance (more balls to accelerate and rotate and contact and lubricate.. more resistance)

The cageless bearing is possible only for adjustable bearings, as for a standard deep groove ball bearing, the cage serves a key mounting procedure (all balls are in near each other, the inner race can slip in, the balls are spread out and cage is installed - spot welded)