I have the adapter, lens and extension tube. They came as a kit when the TS equipment was bought. They are primarily used for closeups or for architectural photography to normalize the convergence of lines in buildings. For landscapes, it would be easier to just stop down to get the depth of field you need, and this goes with any camera.
There is a nice pamphlet put out by Mamiya on the TS "kit". You may want to look it up to see some examples of how it is used.