This is a thoroughly enjoyable course, firstly because of the well-curated material (variety of short videos each covering a theme from a different perspective), lectures, live material (Sarah Meister, the course leader, does live sessions, Q&As and other material monthly or even more often).
The additional recommended reading is really what deepens the critical understanding from the themes covered each week. Whilst it's possible to enjoy it and learn by watching only the course material, the recommended reading (which is lots & lengthy) is actually enlightening.
If you just want to learn a bit more of what you should look for in photographs, you can do the course without the additional reading.
If you truly want to start understanding photography and get a solid base, from an art history and social perspective, really put effort into the discussions, the tasks, the readings and do additional research. You will thoroughly enjoy it.