The main reason I prefer removable batteries is for longevity. Keeping a phone longer than the 1-year or 2-year warranty means at some point the battery is going to deteriorate. Being able to buy a $15 replacement and keep the phone working like it did fresh out of the box is wonderful.
My Galaxy S3 is like that. Got down to only a half-day of usage on a full battery. Bought a new one. Swapped in seconds. Now I'm back to 2 days per charge. Completely extended the life of the phone in mere moments without having to unglue a glass back, use special tools to remove the battery and/or sim cover, and then special glue to reseal the back plate. Now, I'll have to pay a technician to do this for me, and spend a day trying to coordinate where to take it, when to drop the phone off, and when it will be available for pickup. Previously, it was as simple as Amazon drop-ship to my front door, and I had the new battery in while I was walking to the trash bin for the packaging.
My Galaxy S3 is like that. Got down to only a half-day of usage on a full battery. Bought a new one. Swapped in seconds. Now I'm back to 2 days per charge. Completely extended the life of the phone in mere moments without having to unglue a glass back, use special tools to remove the battery and/or sim cover, and then special glue to reseal the back plate. Now, I'll have to pay a technician to do this for me, and spend a day trying to coordinate where to take it, when to drop the phone off, and when it will be available for pickup. Previously, it was as simple as Amazon drop-ship to my front door, and I had the new battery in while I was walking to the trash bin for the packaging.