Second, user-replaceable batteries don't come for free. They come with a series of trade-offs. Small increases in cost, space, even weight. If you plan to keep your phone for more than 2 years, user-replaceable will be more important to you than if you intend to replace every 2 years.

I remember when I switched to MacBook Pros from my Dell laptops. I had two flights a week that were about 5 hours each. I had to buy an extra laptop battery and charger so my Dell would last the entire flight. And sometimes I'd forget to charge both batteries and I'd be back to a dead laptop halfway through the flight.

Then I read the reviews of these new MBPs that lasted 7-8 hours instead of 5 hours, that used sealed batteries. I switched and my new MBP worked like a charm, easily lasting the entire flight every time. One big reason Apple made that advance was entirely because they abandoned removable batteries. They were able to fit more battery using a custom form factor that would have been super expensive to make removable. No one had done this as well before, because Apple was the first to implement good embedded battery conditioning software so they would last a couple years without needing replacement.

Sealed batteries aren't always better, but they typically are for most users and use cases.