Ask HN: Why is my browser so energy inefficient when playing YouTube videos?

I thought this would be a problem long gone in 2020 but it's still not. I had it for decades like everybody else I guess: when I'm playing a video on YouTube using any browser (FF/Chrome) my laptop spinner is going crazy and I can feel the heat. If I download the same video with YouTubeDL and watch it with VLC/MPC-HC or any other player the laptop stays cool.

Any idea why browsers are still so bad at using the specialized video decoding hardware built-in processors for a decade?