Back when I was using a Hackintosh (i7-8700K + Radeon VII), my desktop set-up was drawing 97 watts in idle and on average 250 watts during video editing. This includes the Hackintosh and all peripherals (screen, sound system, USB devices).
Now with the M1 MacBook Pro I am drawing 50 watts in idle and around 70 watts on average during video editing while enjoying a mostly superior and in worst case slightly lower performance in my typical workloads.
So yes, energy savings are massive. Good for me, good for the environment. Switching has been worth it for this alone