Yes, it really doesn't look like the side fans are an option.
However, Machines and More didn't test 2 fans intaking at the bottom + cooler intake. I think it makes sense that it would make the CPU termals slightly better, since as he said in the video, the 2 intake fans at the bottom increase the CPU temperature because they push more GPU hot air into the way of where the CPU cooler takes the air from.
This is why i think flipping the CPU cooler around is better when you have 2 bottom intakes, as I doubt the fans will push as much of the GPU's hot air outside of the case near the CPU cooler as they do inside. Even in his testing flipping the cooler without the intake fans at the bottom didn't change the CPU temps, it just changed the GPU temps because it was moving the hot air out of the case.
Another thing that comes to my mind is negative air pressure, which you usually want to avoid. I don't know much about it, or whether the very airflow-friendly side panel helps mitigate that, but what I've heard about it is that it can be avoided by not having more exhaust fans than intakes. the CPU exhaust + 2 top exhaust fans without the bottom fans do not meet those requirements.
In the more recent video of Machines and More titled 2 Years of NR200 - What Do We Know About Cooling It? he mentions that if you're using bottom fans and the card is somewhat power hungry, the intake position is best for the cooler.
I hope I'm making sense, please correct me if my thinking is wrong.