I keep on falling back to Safari due to the native picture in picture capability. I know, Chrome, Opera, Firefox all now have PiP integrated, but it does not work above other fullscreen apps at all. Since I'm using a 13" mac, I tend to use multiple fullscreen apps, and I love to let a video float above my fullscreen development editor. Also, CPU/GPU utilisation skyrockets as soon as I let a video float, while native PiP (through Safari) seems to be pretty efficient.
Is there a reason why native picture-in-picture is not being used in Opera? Windows and Mac have native APIs to use that, why does everyone reinvent the wheel with their own implementation?