The final law just makes replacing batteries more accessible (i.e. no glue or special screws), but it doesn't mandate battery packs. Also some devices like hearing aids are exempt.
I question whether battery packs would be a good thing to bring back now. USB power banks have 100% interchangeability among many device classes, which is something that not even dry cell batteries achieved. I can choose to leave the house with or without a power bank and just rent one in my city (YMMV). Modern charging wattages are high enough that I don't miss shutting down my Nexus, changing the pack, then rebooting.
It's tempting to say that this could be solved if battery sizes were standardized, but that would inevitably limit device dimensions. For example, I especially loathe how the 18650 has made almost all modern flashlights clunky. I would hate it if Apple pushes for a 4.5mm thick battery standard to kill all foldables because they don't want to enter the market and cannibalize their iPad demand.
Agree - I read this as it will be easy to replace the battery when it reaches its end of life and no longer can hold my charge. It will still take time to replace it, but that's okay since it'll only be done once every few years. It's not meant to re-introduce swappable battery packs, so you won't be able to carry spares on long trips etc.
This is about extending the lifetime of a phone - it won't work properly, even with a powerbank, if the battery is EOL.
The objective is to reduce e-waste, where phones whose only issue is the battery ends up in the trash / recycling, instead of continuing to be useful.
Isn't Apple supposedly entering the market this year though? By the time any regulations has passed, they'd probably already be established. Though I agree I don't really see too much point in making batteries quick-swappable rather than just easily swappable as you say considering it's unlikely to be a true hot-swap without requiring a power cycle.
There are standardized sizes for cylindrical Li-ion cells, and that's often what's inside battery packs. The majority of current mirrorless cameras, for example use battery packs that have two 18500 cells inside, but no two brands have compatible batteries. There are only bad reasons for the lack of compatibility.
I'd be happy if everything sized for it took standardized cylindrical Li-ion cells with protection circuits stuck on the ends. That's common for flashlights and rare for everything else.