Those changeable batteries were horribly unreliable! I've had over a dozen different brand of phones and eventually they all started to black out occasionally when the connections got corroded or otherwise loosened up. I really hope soldered batteries stay an option or I will be buying my phone outside the EU.
Outside the EU, in many cases, device batteries will also be user-swappable.
Companies like Apple greatly prefer (well, when they're not petulantly trying to show the EU who's boss) to ship one design to the whole world. It's a nuisance to have separate design processes, manufacturing processes, marketing materials, etc.
This is why, once it became affordable, the entire industry started making auto-switching power supplies.
Unless hardware manufacturers finagle a way to continue selling soldered batteries in the EU, user-swappable batteries will become the norm again.
