This will be a positive if browsers (extensions?) allow the ability to spoof visibility by site. Most websites have no business knowing if they're in the foreground or background.
Browsers will “slow down” various aspects of pages when they’re not visible, like animations or timers, to save on battery usage on laptops or phones.
Even if your remove explicit APIs for backgrounding, pages can still use heuristics to detect anyway.
That is what it means to have control over your own computing.
Ah, see, there's the problem. The corpo apologists in the room don't want you to have that. The hardware you bought; err, licensed; to them, is their playground.
As an avid idle game player, I'm tired of opening games in different window and having main window not-fullscreen just for the game to play normally
This "tab unloading" is great and all, but not giving us users any control to turn it off is awful