As a proud user of an actually temperature controlled pan, I can do the experiment easily: I cook most meats at a temperature decently below the Leidenfrost temperature, with excellent results. Most veggies, too, but not pancakes. I also find rather hard to imagine that a hamburger or a carrot an egg is actually floating over a cushion of steam while cooking instead of contacting the pan or the oil on the pan. (Even ignoring the implausibility of the Leidenfrost effect supporting a piece of squishy, irregular food and the implausibility of the idea that the pan remains above the Leidenfrost temperature for very long while cooking most foods, much of what’s noteworthy about the Leidenfrost effect is that it limits heat transfer from the pan to the suspended liquid. You are not caramelizing or getting much of any Maillard reaction on a surface that is only in contact with steam at slightly above ambient pressure — it’s too cold!)