This will give you strictly higher image quality that you'd get with a 6x6 medium format camera and cropping to get a panoramic slice - merely 55mm x 20mm. The Canon TS-E lenses will shift in any direction, and have clicks every 30 degrees. You can thus also get a shift somewhat up or down at the same time you shift hard left to get one half, and reproduce the exact shift amount and angle to take the second half. Normally you can change your viewing angle to select the foreground and background that surround your actual subject. You may have artistic conflict, however, if there is a strong rectangular element in the subject that you want to render squarely.
Examples are mirrors, railings, and windows.
If you face a mirror head on, you will be in the shot. If you move to the side, it turns into a parallelogram. Sometimes you have limited access to a fixed display, especially in tight interiors. There might be a ceiling support exactly where you'd like to stand. Set up to one side and shift horizontally to reframe.