In the 2017 Leaf, you can see the front tow hook at 4:40 into this video, and the rear loop at 5:00. It looks different from your photo.https://www.youtube.com/watch?v=1DJa_Z_00Nw
In your photo, it looks like there is a threaded hole facing downwards. The hole doesn't look big enough for a tow hook (you should be able to stick a finger in a tow-hook hole). And it's pointed in the wrong direction. Imagine a tow-hook like a giant"screw eye" pointed 7 inches straight down. Imagine that the car is stuck in the mud, down a 45-degree freeway embankment. Pulling on the end of such a tow hook would just turn the tow hook bolt into a 7 inch lever, which would put a twisting torque onto the frame member.
It seems more likely that those vertical bolt holes you see could be for mounting a trailer hitch.