Is for you the "brand new hardware" your desktop which spends hundred of watts per hour or your mobile phone which has to survive the whole day without recharging his 5 Wh battery but still let you surf the web with all the stuff you take as given? Making optimizations that work good with lower wattage CPUs is a good thing, unless you limit yourself only to the non-battery devices.
Mobile architectures are typically only a tock away from desktop architectures, who aren't really guzzling energy with these optimizations (the deep pentium 4 pipelines are behind us!). So if technology marches forward, there isn't some mobile version that is frozen in time just because of energy efficiency (indeed, good branch prediction saves energy also). There are no 386 or 486 CPUs to care about now, while P5s are limited to that Phi HPC product.
Is for you the "brand new hardware" your desktop which spends hundred of watts per hour or your mobile phone which has to survive the whole day without recharging his 5 Wh battery but still let you surf the web with all the stuff you take as given? Making optimizations that work good with lower wattage CPUs is a good thing, unless you limit yourself only to the non-battery devices.