Specialized device for a task
While modern people can use smart phones for almost anything, I came to conclusion that while it is jack of all trades it rarely gets things right. I do not know if it is because I am old fashioned or just too slow, I am unable to accept using touchscreen devices for longer than few minutes (moments).
The main advantage in using specialized device is for me to have specialized functions such as special screen, better battery, keyboard or special keys/buttons, and overall environment which allows me to focus on the given task (or just relaxing) without being disturbed by some annoying notifications (Like most smart phones do when you use them a bit more). In other words I am able to separate tasks and focus only on them.
As a disadvantage I can only think of having to carry multiple devices when travelling. But with smart phones it is not that different either. In order to get these phones as thin as possible the batteries are relatively small and when you use the device it will quickly use all (or most) of its energy and I am forced to carry some bulky battery (power bank they call it).