1. "Magnification", "3D view", "better color" are BS, or more politely expressed, the imagination is playing a game with some.
2. Stitching can be completely adequate in some situations, like landscapes.
3. Stitching is not always working with architecture, and perhaps never in studio. Moving subjects are out of the scope in most caswes (when these moving objects are just the main subjects).
4. The dynamic range can be a big issue even there, where the stitching is the best, in landscapes. Although it is possible to capture an even larger dnamic range of the scenery in several frames than an MFDB can capture in one frame, the processing can be extremely laborous. Furthermore nothing help, if the large dynamic range of the scenery can not be separated in frames, except HDR - even more work, less fine result (and today's HDR results are not everyone's taste).
So, when time and effort are non-issue and it is not a problem, when a certain situation can not be solved adequatey, then yes, stitching. However, some can say justifiedly, that they can make several new projects in the time required to process a high-quality stitching.
There is another side of the issue. MFDBs too have limits; what if even a 39Mpix image does not suffice or the angle of view is not large enough? I hear already some: then stitching several MFDB images. Suddenly stitching becomes acceptable. LOL.