Why would you want to reproduce the art of the past?
To learn how it was and is done.
For example, one variety of Japanese ink drawing, Ukiyo-e, is very different from western drawing styles. The side of the palm does not rest on the paper, the brushes are very stylized, and endless practice is needed to produce something artistically pure, like a mere stalk of bamboo. In learning it, you not only learn minimalism, but the projection of “spirit” with the tiniest stroke of the brush.
It can be compared to some of the later works of Matisse, and shows how even a squiggle to depict an eye, can express far more depth than a realistic looking eye. Picasso, likewise, created an extraordinary work of a nude woman’s backside, with just three thin lines.
At a more basic level, learning how a classical painting was developed by its artist teaches a methodical order to realism. Everything from the artists’ sketch studies, how they created a sense of perspective and balance, and made pictures that were relatively accurate, not caricature or illustration.
Then, there is cross training. Learning different media so that students are not close minded about the tools they use to create.
They also need considerable depth to find their artistic subjects. To understand how virtually everything can be made artistically relevant, naturally and artificially. This would require skills such as photography, and even research to understand the context of the study.