Plomien, forgive me as your original picture is a gorgeous colourful garden but I don't see a great difference in the second? maybe the flowers seem to be leaning slightly.. 
I think it improves the shot of the flowers immensely. The original shot is OK but the perspective is very flat so it's not an interesting photo IMHO. There's no real subject. After the tilt shift the flowers stand out as the subject, and it has a lot more depth.
There's no obvious reason why the shot couldn't have been taken from this angle originally in this case, although you might have struggled with the depth of field but in other cases, you simply can't get the perspective right and have to shoot from where you can so I can see an advantage in being able to do this sort of stuff.
Not quite so sure about HDR. :-/ It wasn't necessary in this scene anyway, IMHO. Used subtlety it can rescue shots where the camera just doesn't have the dynamic range to capture it but when over-used it tends to take the life out of pictures, IMHO.
Again, though, just my opinion, and it's a very subjective thing.

Kevin