My 2 cents here.
I had a small calcomp some 12 years ago and I did not use it much. I reduced the sensitive area to minimize the wrist movement. But I did not really stoped using the mouse as my primary input device. The tablet stoped working and I did not bought another one for a decade.
I have an Intuos 5 now, but I only use it on some specific Photoshop retouching, when you need to "fill an area" with strokes.
On vector drawing I edit the nodes with the mouse becouse I have better support using the friction of the mouse with the table. I have the pointer on the right spot and after that I click it. It dosen't move.
When you use a tablet you need to hold the pointer on the air, and "aim" to a spot and move the pointer to click. I'm exagerating a bit but that is the idea.
Well I'm a maniac on node manipulation, so in some cases I use the keyboard (with a precision of 1/10 mm. So in those cases The tablet don't work for me.
But I'm still working on painting something more freely (and pretty) with my tablet.
The tablet is a free hand tool. If you use the keyboard mostly and need the pointer to stay in one place (node editing, a tab on a program) you probably should stick with the mouse. The mouse does that, stay on the table. Each time you need to point you need to grab the pen and look for the mouse location again so your pointer move.
If you like free movements, you controll your strokes, you write in every paper and sketch things in a napkin every time you see one, yeap probably a tablet is for you.