I feel live you shrug off undervolting a bit. You said it makes the card run slower, but that's not necessarily true afaik, it is just more unstable. You set the voltage limits and clock rates at specific power level bands. If you get it right, you use less power per clock so can increase the clock rate and thus performace for the same or less power and heat. This makes sense for example in crypto mining where you have a consistent heavy workload, all the fine tuning can pay off.