In Safari in macOS, Netflix uses about 10% CPU showing 1080p. With Chrome, it uses 40% playing 720p. With Firefox, it uses about 75% CPU and my fan turns on. I'm guessing it's higher on 1080p.
I don't think Netflix has any interest in you using a proprietary client. They don't gain money if you watch one way or another. They gain money if you keep paying them your monthly fee.
EDIT: Installing this extension took Chrome CPU usage to 75% for me.
Also, I'm not saying that users shouldn't be given the choice to use their CPU resources to run Netflix. Maybe it would be better if Netflix were just more transparent about it. "By default, we only display video with 720p in Chrome due to high processor usage. Click here to change that preference or watch with Safari whose direct rendering means 1080p video using less processor resources." That way, users understand the problem and can decide they don't mind other programs becoming sluggish or the fan running or whatnot. Of course, companies generally don't like giving users details.
I don't think Netflix has any interest in you using a proprietary client. They don't gain money if you watch one way or another. They gain money if you keep paying them your monthly fee.
EDIT: Installing this extension took Chrome CPU usage to 75% for me.
Also, I'm not saying that users shouldn't be given the choice to use their CPU resources to run Netflix. Maybe it would be better if Netflix were just more transparent about it. "By default, we only display video with 720p in Chrome due to high processor usage. Click here to change that preference or watch with Safari whose direct rendering means 1080p video using less processor resources." That way, users understand the problem and can decide they don't mind other programs becoming sluggish or the fan running or whatnot. Of course, companies generally don't like giving users details.