We swap spare batteries all the time:
- When my wife forgets to charge her phone and is going crazy leaving for work.
- When we're on a camping trip, it's simple to take spare batteries.
- After I spend all day on the phone and then want to go out all night. Just swap in a charged spare and I'm good to go.
- After my daughter spends a long time using Slingplayer watching TV and my battery is about dead, I don't mind... just swap in a spare.
People without the ability to use a spare battery, often adjust their lifestyle to their phone. I believe the phone should adjust to mine.
Swappable batteries also make a phone more attractive to business usage, and they could be very handy if video calling gets popular.