I really like this e-learning topic but I still do

I really like this e-learning topic but I still don't get it. What is there to benefit from a "call to action" links to click on? Or a dial pad? If a teacher wanted to send a video home with all their students to learn how to find the area of a square why wouldn't they just upload a YouTube video? This shouldn't be read into as a challenge to your opinion on this particular market, I genuinely don't get it, and I assume it's because I'm missing a fundamental component of the technology, which im guessing is its tracking ability? Surely companies know whether an employee watched a compliance video or not. I get the sales aspect but not the e-learning... is our tracking ability that much more advanced or something? Sorry all if this is way too much of an elementary question but it's about time in this investment to begin wrapping my head around this!