I want to be able to change the battery far more often - possibly every 8 hours if I'm using the phone a lot during an off-road adventure or other adventure where having a charging device isn't a great solution. When I used to travel a lot I had a smartphone with a replaceable battery and I carried several replacement batteries. Going from 5% battery life to 100% battery life in the few seconds it takes to change the battery was a very useful thing when I wasn't able to charge the phone easily. And no, battery charging bricks are not convenient. They are way more bulky and take far longer to charge the phone than popping in a fully charged battery.