That's true, but I think the fact that you get light reliably every day is still a big point in its favor. It's probably a lot less mass total to send up twice

That's true, but I think the fact that you get light reliably every day is still a big point in its favor. It's probably a lot less mass total to send up twice the solar panels and 18 hours' worth of batteries vs half the solar panels but 16 days' worth of batteries. Solar panels are pretty light; batteries are not.