I use PIP a lot in Chrome while browsing Reddit. If I see a video link, I can play the video while continuing to scroll through Reddit comments.
(YouTube PIP is kind of difficult to discover; you have to right-click, move the mouse off the menu, and right-click again to get the native right-click menu, which is where the PIP button is.)
You mean open in another window, arrange and resize that window to not get in the way while making the video visible, hoping that the website layout doesn't make that close to impossible, and still not easily being able to have it stay on top of the window you interact with... instead of a single click that does the right thing?
(YouTube PIP is kind of difficult to discover; you have to right-click, move the mouse off the menu, and right-click again to get the native right-click menu, which is where the PIP button is.)