Try playing a 4k@60 YT video with HW acc. turned off and compare the power consumption on the laptop.
Edit: I did a small test running 4k@60 with HW accle turned ON & OFF.
Turning off HW acceleration basically doubles the power consumption for 4K@60 YT playback. For Laptops/notebooks it might mean reducing the battery backup to almost half for video playback.
Note: After turning off HW acceleration, YT decided to switch to VP9 codec instead of AV1. Otherwise, the difference might have been even bigger as AV1 codec is more complex and taxing on the CPU to decode.