I definitely think there was an argument to go for it. You had plenty of field to work with, not just the endzone, so I think 4th and 4 from the 9 is easier than 4th and goal from the 4, say. If you’re stopped, you’re still ahead by about 15 yards of field possession compared to giving it to them on the 25 after a touchback. Your defense has played well all night so you’d be trusting them to prevent the Chiefs from at least gaining 45 yards or so to move from their own 9 into FG position. That’s true either way, but by kicking a FG, you’re guaranteeing that the Chiefs would be using 4 downs the entire drive, whereas if the Niners had tried and failed the Chiefs would probably punt on any 4th down in their own territory. All things considering, I think I would have gone for it.