Splodging a big ugly and pointless Picture in Picture icon over a video is not the best user experience in all cases. As the application developer it should be up to me to make that decision, not Firefox.
Personally I make use of this feature a lot, it's one of the reasons I prefer firefox over chrome (though there's things to accomplish similar things on Chrome, but firefox native support is better... you even get some controls over the video on the pip window).
You are over-exaggerating it to get what you want, aren't you? I had to go back and check. It appears only when you roll the mouse over the video and it's inconspicuous even then.
The way I interpret this, the original description mentioned "you can't display your ads, overlays or anything else and thus it breaks player implementations of content providers" - and I am pretty sure Firefox's decision for PIP feature was _specifically_ to allow one to watch picture without ads or (often terrible) players by content providers.
Now, the commenters understood that, and rightfully assumed that asking "hey FF, you made a system to block ads.. can you add an attribute to disable that?" would get their request denied, again. So they all say words like "enterprise system" to explain why they cannot give an example.
Note that any time there is a problem with specific website URL (like mirroring in comment 23, or video controls in comment 34 and 36) get assigned separate bugs and fixed. It's only vague "enterprise system" use cases which get rejected.
(Well, that and spanish learning system in comment 29, which needs to be able to track how of the video was watched. I am split about this - from one side I see the usefullness of knowing that sometimes, from other side this is exactly a kind of creepy feature that firefox is known to not implement)
As an application developer you're obviously shipping an executable or an app, so why is Firefox part of the equation?
Totally lost rn. Could you please elaborate?
You want to take the decision away from the user because you claim that user experience is better.
What is so special about your website an your video that nobody ever would want to use a general purpose feature for that video?