If you prefer text that's fine. But you must be cognisant that a very large number of people do not, and that in many cases you're losing a lot in the translation - including that the translation may never be made in the first place. Personally, I am fine with both. There is a right tool for the job.

> I don't have sound because it'd be a security vulnerability

This just sounds to me like a kind of narcissistic paranoia. Dude, the NSA isn't spying on your youtube habits, and if they were - the VM, or anything else, wouldn't help you.

Do you or did you consume all of educational content through static text and images only? Or maybe, just maybe, a lot of things were explained and shown to you?

Lectures and rambling are distinguishable.

Some of my professors did ramble, now and then, but that was mostly OK.