I travel internationally pretty often. I also use my phone as a GPS when driving. Both cases have resulted in me having my battery at under 10% and desperately hoping I have enough power to get to where I need to go. And always having a charger or backup battery of some sort is just inconvenient.

For the people who are at home 90% of the time, they're probably not using a phone the whole time. They'd be better served by a desktop.