You can, in principle, but it's a pain in the bum - and you still have to write down what was actually said if you want to sure of what is being said. With something like theology, philosophy or science, the exact terminology is important.
I remember so vividly my first term at university. I had to learn all about atomic structure and spectra. It was tough. I had a couple of books and I would read a chapter, go back, read it again, then go back and re-read particular passages that I could not quite follow, and compare them with the other book, ask fellow students and my tutor about them etc. Trying to do that sort of thing from a video would have been impossibly painful. If you really want to understand something of any complexity, you need to see it in words, (and, this being physical chemistry, equations, with some diagrams thrown in, but that's by the by). A video may help, to give you an overall impression or to introduce a topic but that's all it can do. (In fact, we were once shown a video of the Stern-Gerlach experiment, and I recall the hilarity with which this was greeted by the students. It was pitched too low for them and didn't really get into the nitty-gritty. But what a pain to sit through 15 mins of this and only find out at the end that it was going to leave you short of a proper understanding.) The spoken text in a 15min video can generally be read in 2 minutes. That's how wasteful it is.