They are talking about iPad Pro as the primary example of M4 devices. But iPads don't really seem to be limited by performance. Nobody I know compiles Chrome or does 3D renders on an iPad.
It’s all marketing toward people who aspire to be these creative types. Very, few people actually need it but it feels good when the iPad Air is missing a few key features that push you to the Pro.
More practically, it should help with battery life. My understanding is energy usage scales non-linearly with demand. A more powerful chip running at 10% may be more battery efficient than a less powerful chip running at 20%
