The people who need this feature should go buy one of the phone models with replaceable batteries.

Reading the comments here, it's obvious that the replaceable battery fans can't even agree on what they want. One commenter wants the back covered in tens of screws for waterproofing. Other commenters want the battery quickly replaceable so they can do hot swaps without missing a beat. Some people are sharing links to phones that have replaceable batteries and getting responses from people saying they'd never buy that phone because it's too big, too ugly, or other reasons.

This is an impossible debate because one side has convinced themselves that it's possible to have their cake and eat it, too: They believe that removable batteries can be implemented without any tradeoffs and the only reason they're not removable is so the phones are forced to become e-waste, which requires you to ignore all of the low cost battery replacement services available.

I use a lot of rechargeable AAA and AA batteries. They have lower voltage than alkaline batteries (by design apparently), which is not normally an issue, but sometimes is a deal breaker. E.g. my thermostat did not like lower voltage AA batteries and shut down prematurely a number of times.

There's challenges adopting standardized rechargeable batteries, e.g. trying to recharge alkaline batteries risks fire/explosion (and you know that will happen far too often given the number of people out there), but if we have had standard battery sizes, voltages, and capacities for rechargeable batteries, things would be so much better.

There are a few flashlights that have USB PD power bank functionality and also run on 18650 or 21700 rechargeable, replaceable Li-ion cells. I bought a Loop Gear SK05 Pro to replace Anker power banks for this use case.

I have a magnetic wireless power bank that I put on my phone and I can continue using it as normal.

But you can plug in the battery pack and keep working…

Nobody needs to do that with a mobile phone.