Running non-ethanol is not a bad idea if you can find it. Paying for premium in most passenger cars is a waste of money unless the manufacturer requires it for your engine. The only difference betwen premium and regular is that premium gas has a higher octane rating. The octane rating tells you at what compression ratio the gas will begin to combust. Ergo, higher compression engines require higher octane fuel. Most racing engines run 110 octane race fuel.
I think it comes from a “more expensive must be better” mentality. Most folks don’t understand that that simply isn’t the case with gasoline. As you both noted, unless the engine was designed for high-test (remember that word?), you’re just wasting money.
As do non turbo prop aircraft engines — generally speaking.