Imagine it's one device but when you pull it out of your pocket, you pull it in half and only slide out a touchscreen leaving the battery and other guts in your pocket. With some magnetic clips, it could be seamless to slide it back into your pocket to become the larger single brick again which it stays as you take it all out at night to plug in and charge.
The thinness is not the feature, the modularity is. The thin touch screen can connect to your laptop as well as your phone. But it will also look very elegant. And i am hoping such a tech would apply to monitors and desktop peripherals as well. You wouldn't have to worry about the looks of your phone, dropping it and a lot of other annoyances. In the distant future maybe this handheld screen can expand and shrink on demand as well.
