Phone usage is getting more intense as we move from mere passive consumption to having them as creative (compute) device. "Heat" is sort of reflection of that.

I want to see more optimization to reduce the heat from both hardware as in this case and in software side as well. I guess it is easier to show enhancements about hardware made to address something such as heat or processing but comparatively difficult or abstract to show software optimizations?

From a keynote perspective, I guess showing software optimizations is less cinematic and not everyone can appreciate them as opposed to new or beautiful looking hardware.