The ball bearing offers less friction, but the bushing offers better reliability (no moving parts), and a greater savings in cost to produce (which I doubt is being passed along to the end user).
Ball bearings in particular are unreliable if there is a heavy load to be carried. This is do to fact that being as round as it is humanly possible to make them to reduce friction, it also results in the load being carried on a single point of the ball. This can dig a hole in the race as the pressure of the load goes up.
The balls not only roll as a result of frictional forces generated by the turning bearing race, but they spin as well which allows the bearings to resist developing a flat spot. This tendency to fail under heavy loads (cars getting heavier) resulted in the automotive industry to switch over to tapered roller bearings at the axles instead of the ball bearings that they used to install back when cars where horse drawn carriages propelled by basically a lawn mower engine.
Bushings made of semipermeable materials, such as silicone-bronze, can carry heavy loads at a fraction of the cost of a roller bearing (which is also more expensive to make than a ball bearing). The oil that is embedded in the matrix of the molecules support and lubricate the shaft at a much lower cost. And it will last a long time, provided the oil that impregnates the metal stays put (you will notice that the bushing was shipped in a hermetically sealed plastic bag and that the bag was oily inside). Should the oil be squeezed out under excessive loads (the metal is like a sponge in that regard), or more likely evaporate due to excessive heat (such as encountered by dogs locked in a car parked in the sun) then the reliability in service shifts back to the ball bearing.
I will let you decide which is better.