From a performance driving instructor. I get youre not going to kill your clutch day one by incorrectly using it. But its unnecessary wear and stress if you arent blipping your throttle to try and somewhat match the rpms of your engine and trans. Why would performance cars have rev matching advertised as a feature if a clutches function included it in the first place? Come on man, this is common sense. Again, I get you can get away doing it, its not gonna kill your clutch / trans right away but its unnecessary stress and wear.