The feature to auto-enable Picture in Picture when switching tabs is a really nice expression of the principles of "respecting the user's intentions", and "avoiding unexpected behaviour".
https://orionfeedback.org/d/7363-automatic-picture-in-picture-pip-when-switching-tabs
There are many moments I would like to continue watching a playing video while wanting to foreground another app, like note taking or messaging.
Indeed, this is the default behaviour of Apple's player on iOS. While the windowing UX models are obviously different, the pattern could work very well on desktop in single screen settings, esp. smaller laptop screens, where it's more likely that the windows of background apps are obscured.
Additionally the exit PiP button in the player is a quick means of jumping back to 'where I left off' i.e. the video source browser window and tab where I started playing the video.
