Those bulky accessories are a good thing! "Smaller and sleeker" also means "easy to lose". If my phone was that small, it would disappear after less than a week and I'd never see it again. The one I have is hard enough to keep track of as it is.
Plus, things can get particularly upsetting for those who have dogs, especially larger ones. In their minds, there are only two kinds of objects: those that are meant to be thrown/fetched/chewed, and large furniture. Any other distinctions do not exist.
"It's a machine that goes... ding! Made it myself. Lights up in the presence of shapeshifting DNA. Also, it can microwave frozen dinners from up to 20 feet and download comics from the future. I never know when to stop."
First thing I thought of when I saw that case with backup battery. Haha.