If something is detachable or is a removable option, it will likely never be available when you need it.
I seldom have my USB webcam with my laptop when I need it. My laptop’s removable optical drive is always removed (to reduce the weight); the same goes for my headset. If I had an SLR camera, I would still be more likely to use a compact camera or my phone to take pictures. And my next phone will likely still have a built-in physical QWERTY keyboard.
So why do we kid ourselves that we will cart yet another piece of optional thing around with us? If it is not built it to a piece of technology central to our daily lives, one that we tend to have with us all the time, then we probably won't have it when we need it.
If you want to make your products/services more useful to your customers, or make your business tools more useful to your employees, you need to carefully consider the user context.
- Where is the user most likely to need to use this new tool?
- What other tool is the user likely to have with them already?
- Can you integrate the two?
- If not, can the new tool subsume or include the functionality of the existing tool?
- Can the new tool provide such an important function that users will consider making that a must-have tool?