I performed a simulation assuming that a 2018 Leaf would DCFC for 960 miles. My simulation indicated that the trip would take 28.2 hours traveling at 45 mph with an average peak charging speed of 25 kW and that the trip would take 30.7 hours traveling at 70 mph with an average peak charging speed of 14 kW. The simulation assumed higher charging speed for the first couple of DCFCs when the battery is cool.
Is saving 2-1/2 worth traveling 25 mph slower than everyone else and risking getting rear-ended? I think not unless you just absolutely have to get there sooner. With such a small advantage in travel time over a long distance I don't think reduced speed is worth it.
I'm not worried about cooking the battery. With all the controls Nissan put into the 2018 Leaf thermal management system I don't think there is much risk of premature battery failure. And even if the battery fails, because I drove a long distance at the speed limit, Nissan would have to honor their warranty.