Of course I'd use energy differently if it cost more. If I had to generate energy by pedaling a bike, I'd consider it costly indeed. So what? Energy doesn't cost as much as it would if I had to manually generate it, and who are you to say allocation decisions made under that regiment are good and ones made under ours are bad?

Wouldn't your argument also compel us to use steel as if it were gold? Salt as if it were saffron?