I'm only familiar with the load output on Victron controllers, so everything below is based on what I know about them, some or all may apply to your aims controller.
One advantage of separate outputs for battery and loads is low voltage disconnect. With a LiFePO4 system, this is probably redundant, as your BMS can handle this as well.
But this doesn't make the feature useless, it can be used creatively in any way you can think to utilize it. Maybe you have an icemaker or a hotwater heater that you only want to run when the batteries are >80% charged for instance.
In the case of the Victron, there are various other things that this enables, there are several algorithms or adaptive settings that can be used on the load side. But I don't know much beyond that.