Yes, it's likely a low output charging circuit- often an option on motors of this size. It means you can more or less 'trickle charge' your batteries while running - at least, for example, you might keep up with nav light draws when motoring at night. Not sure of the typical output, but it wouldn't be designed to keep up with fridge-type loads.
Better than nothing, though, if it's functional.
Here's a thread from earlier here in SN that might help you out.
Small outboard charging systems. (Tohatsu/Nissan in specific.)