The software, does have limitations also. There is always limitations to how much the software can in-between 2 images.
Characters that topology change too much will require some planning adjustments. The aspect that animators have to keep in mind is when there is "occlusion". This means when one body shape covers another. Occlusion is interesting because the software does not have a brain to determine missing data, so the user will need to think before moving into in-betweenig.
We have ways to by pass this of course, but this was to give you some perspective.
CACANI is not a magical software, we simply figure ways to make a process that wasn't tackled by others software possible. But there is always limitations mind you.