The only time I ever used a removable battery is to cut power to my phone to do a hard reboot because it stalled.
While this is useful, I wouldn't pay extra for it nor would it be a deciding factor.
SD Card? Why? What do you people put on your phones? I'm lucky if I break 3GB with apps. Photos, movies, etc. on Dropbox where I have 70GB worth of stuff.
And various social media apps have fairly large local caches. Examples include instagram, tumblr, and vine.
So if you're just using a bunch of cloud services you don't need a lot of space, but not everyone uses their mobile that way.
As lame as it might seem I just keep a spare battery with me at all times when the unexpected happens and I'm out later than usual or just use my phone too much.
I guess a case with a battery built in work work just as well, but I'm not willing to add the extra bulk.
Oh and get the 32GB model, that was obvious to me....
And whats worse is that if your streaming it, your gonna be eating your battery even more.