You can learn to play guitar better watching YouTube videos - it doesn't replace practice, it helps inspire and educate by bringing talented practitioners to the world in a way not possible 40 years ago.

Why not surgery?  Otolaryngologist Martin Young writing at KevinMD.com argues that because he has learned so much from watching more experienced surgeons work, peer-reviewed videos might be the wave of the future - obviously a South Korean teenager may be fun to watch play guitar but he is not going to be a source for best surgical practices.   
 Here’s the idea. Teaching hospitals and medical schools could find sponsorship from big pharma and surgical companies within all disciplines to use their own experts to record short five minute video clips on skills and tips that are worth disseminating to the benefit of doctors and patients all over the world. I can think of twenty areas at least within my field that I would love to see presented in this manner.
Now, why do mega-corporations like universities need outside corporate sponsorship to produce videos, since they already have the people on staff?  No idea, he is a doctor, not a business guy, so maybe he thinks that one corporate funder is magically better than another - but if it's a good idea, it just requires someone to do it.   It doesn't always have to be someone else footing the cost, one IT guy and one programmer could create the tool to host the videos and make them sortable and rankable in a day.

 It won't be me.  One thing I have learned is that people have a sense of entitlement that everything should be free on the Internet but they should be paid, so if I call up a medical school and say I want to film an expert doing surgery, I will get a bill in the mail even if their future residents watch it for free.