This post is a longtime in getting written as I have had a Wacom Bamboo Fun tablet for many years and one of the issues was getting Gimp to use the pressure sensitivity of the tablet. The steps covered in this post can be used with most if not all of the Wacom family of tablets.
The question should be why not! Using a program like Gimp or Inkscape it is always easier to have the feel of a pencil, brush, etc.. then using the mouse, which is doable.
It is much simpler to get the tablet to address pressure sensitivity and the eraser than you think. The steps described here will work no matter what OS you are running Gimp or Inkscape on.
First step is to make sure the tablet is recognized by the OS, with Windows and OS X it requires installation of the drivers. With Linux it is much easier as usually the OS will detect and load the drivers.
Now that the tablet has been detected let’s get in GIMP and change a few settings.
You have to configured your tablet using, Edit>Preferences>Input Devices>Configure Input Devices> WACOM Tablet Pressure Stylus, and set the “Mode” to “Screen”.
Set WACOM Tablet Eraser Mode to Screen as well. Click Save and Close when you are completed.
You need to set the “Brush Dynamics” to “Basic Dynamics”. “Pressure Opacity” should also work, as long as the configuration “Mode” is set to “Screen”. As seen in the image above.
This should allow you to use your “Pressure Stylus/Wacom” as it’s intended.
And that is all you need to do to enable Gimp to use a Wacom tablet correctly!