This is a variation of the question, "Should I capture the final image in-camera or create the image in Post Processing?".
The answer depends on your goals for the image. I use both approaches. I like the photographic challenges of capturing everything in camera. So, sometimes my set up looks like a Rube Goldberg contraption. On the other hand, in some cases I could only get the image in post processing. Remember, even Ansel Adams was adept at post processing; read about his efforts to burn or dodge parts of an image in his darkroom.
However, there are a couple of items to consider:
One consideration, is time. In general, I find that if I can capture the image in camera, I spend disproportionately more time outside photographing and less time in front of a computer.
Another consideration is use of the image. In this case, the tilt shift lens will minimize artifacts that might be created in post processing. Publishers may prefer to have the image without those post processing artifacts.
Also, take a look at Matt Grum's comment below - he adds a couple of additional, thoughtful considerations.