IMHO: Videos and MP3s are linear and non searchable. Transcripts, texts, ebooks are searchable, great for copy&paste note taking (unless copy is forbidden), and can be speed read. Videos are great for entertainment, but my absolute LAST CHOICE for education.
If you can't resist making videos, make them hi-res [e.g., Camtasia] not YouTube "quality", AND provide transcripts.
Some "gurus" advocate expanding a small amount of information into a large collection of CDs. Great if you only plan selling to idiots.