An article about 4 different vehicles and 4 different engines that have a markedly lower compression ratio than our dearest coyote. You can't use this article as a blanket statement. The need for higher octane varies from engine platform to engine platform. Octane is resistant to knock. That need increases as the compression and heat within the chamber increases. That's all it is. "Premium" is a misnomer but the engines that are designed to run higher octane gain plenty from it and should use it. Case in point on how much of a power bump the gen 3 gets from running e85 (100 octane) alone. Even 93 holds it back.The extra 1-2mpg you might gain in fuel economy does not compare to the +50 cents or more a gallon in cost to fill it up. The difference in hp is less than 10%. So your choice.
Higher octane is one of the best ways to make a small engine do more work with less. You either run big displacement to get a bigger oomph, run higher compression to get a better oomph, or use boost to get a forced oomph.