If it has a starting battery, but isn't designed to charge the battery,
it would be the first such generator I've ever seen. What would you do
if you were designing it? Charge it or put in an outlet and expect the
user to charge it? Any instructions in the manual that tell you how and
when to charge the battery? Seems if it were required, that would be in there.
The wiring diagram in the manual also clearly shows the separate battery charging circuit, so there's that.....
If you need unregulated, full wave rectified DC, 12V +/- X% to use for
something else, then get the cables. Otherwise, it doesn't matter.
I have a battery charger and if I needed
to charge an auto battery when the power is out, I'd use the generator
to power the charger. So far, that has never happened here.
You're not Jesse Pinkman, are you? On Breaking Bad they needed to use
a generator like that because their RV cook lab had a dead battery in
the middle of the desert 20 miles from civilization. It didn't work
though, they mamaged to set the generator on fire while trying to start
it. Jesse was very confused.