It allows the inverter to supply loads from available PV and an accepted AC source even when no battery is connected. That can be useful during staged commissioning or in an off grid solar system designed to use solar whenever it is available without installing storage immediately. The off grid inverter does not create backup energy by itself, so loads will lose support if both PV and the accepted AC source are unavailable. Batteryless operation should therefore be treated as a source-flexibility feature, not as a substitute for battery backup.
