Colorization - what was it's purpose?

[Dunsel]

The main problem with the colors is that the painter does not mix consistent batches and is not able to put down the paint evenly. I don't know whether this is because of the preparation process, the materials, the tools, the skills or a combination of all of those. But the painting is objectively subpar and appears sloppy.

The painting makes the manuscripts more interesting, or attractive, which is why it was done.
The colours were not there to help identification of the plants.

Thanks for pointing this out. I think you're both correct. Perhaps it's not the rush job I was seeing.  Perhaps it was just a combination of a lack of skill forced by, "colorful illustrations are what's expected."