An example of the versatility:
I took both these shots at f/8, the shutter speed is slightly different due to the light changing but that won't affect the DOF. Ignore the difference in processing.
This one I tilted the lens slightly down so the focus plane was more in line with the mountains. I don't think you could get such a high level of clarity throught the frame with a conventional lens, even at f/22. I think most lenses start getting less sharp around f/8.
Same shot but this time tilting the lens away from the focus plane. Still at f/8 but I have a shallow DOF which is hard to achieve with a traditional 17mm.
The top shot was incredibly difficult since changing the tilt even slightly will affect the focus plane. I didn't have a tripod and so I had to hand hold the shot, zoom in to check focus, adjust the tilt, recompose, zoom in the refocus, etc.
Pack a tripod.