The EU with its mama energy again.
I use 15 Pro. I don't like the new aluminium iPhones much. So I just went it to Apple service center and had the battery replaced. It costs just 90 euros and I now have a brand new phone, basically.
I very much prefer my phone to be thinner, water resistant, and have a larger battery compared to being able to do it myself.
Why pay 90 when it could be 20
The law is not about you, but about everyone: 1) Apple doesn't have service centers everywhere: some countries/cities/small towns don't have them 2) Apple doesn't provide service for older devices 3) making it easier doesn't mean you'll be able to swap them live as we did in the 90s, but it means you could do it at home with a reasonable set of tools instead of sending the device to some shop that would need to unglue, unsolder, ...