Well, I was actually hoping for links to actual scientific data but...
The video is a nice explanation of how lithium-ion batteries work. And, it does say that batteries can be damaged by draining to 0% (true) and therefore, that you should charge your battery at 30-40% but it never explains why that's better than say, 20% which is when Apple starts warning you. Why would Apple wait until 20% if it was better to charge the battery at 40%? Also, there is no mention in the video that I caught that said you shouldn't charge it fully and that fast charging was bad. In fact, it even says that batteries have circuitry to prevent overcharging.
Couldn't find out much about "Branch Education" and, sadly, their citations are not clickable. Of the ones I was able to access, only one had anything to say about charging under the heading of "What might make my phone last longer" (note the words "might" and "phone", not battery), "Keep your battery charged about 50%" (yet another percentage). It was a slide deck from a battery company with no citations of its own.
As was noted in the user tip I linked to, there's a lot of misconceptions about lithium-ion batteries. I think it's important we don't promulgate them.