Yes ARM will be more efficient than x86 at low loads, but Qualcomm hasn't shown the efficiency compared to the own predecessor X1. It would be nice if Qualcomm could achieve efficiencies at the level of Apple Silicon. But it's really nice, that Qualcomm achieves this efficiency without any E-Core (bigLITTLE-concept).
Qcomm can't be trusted after how badly they botched the last release.
Until they release tests that can be independently verified, don't bother releasing any more first party slides.
Let's see the power efficiency improvement and if there are still any/many games that can't run.