I often see self-defense folks, gun guys, weapon "experts" and martial artists of varying styles mocking the concept of learning via internet youtube videos or DVD's, but I think their criticism is unfounded . I've looked at the resume at many of the people throwing out the derogatory comments and notice repeatedly that a lot, if not the majority, of their training often has come from various seminars. I'm not referring to just some random anonymous guys on forums, but many prominent defense instructors. They teach every physical component of defense(firearms, blades, impact weapons, unarmed Combatives) and feel qualified to do so with the bulk of their "expert" knowledge being derived from these seminars while being dismissive of anyone who didn't receive all their training in person. I've been to a lot of seminars in my 30 years of involvement in self-defense and they have all pretty much been the same. They are generally short on detailed information and the material is diluted and condensed to fit in the allotted time(not necessarily a bad thing in itself) and you don't receive a whole lot of one on one instruction. Most often the instructor stands in front of the group lecturing(usually much more so than interacting and discussing), demonstrating and occasionally walking around giving a few pointers as the attendees practice the techniques. How is that all that different from watching a video of the seminar? I've attended many seminars and watched videos of seminars and to tell you the truth, I never felt they were all that different although there are a select few trainers that give better (needs to be small group) seminars than others.
Now, if your goal is to be a recognized "certified" authority or authentic "expert" whatever that means to you(it's definition often differs) in the entirety of a particular self-defense method or system, then your probably in anyone's perspective going to need actual first hand formal, live, in person instruction from a "recognized" actual instructor as there are many subtle nuances and on sight immediate direction and correction that can only be made with them there with you in person for intensive training. But, were talking about just learning some practical effective self-defense techniques and often that context, simple is best and in certain cases, some forms of in depth training are unnecessary, overly complex and actually wasteful and a hindrance to that goal. And we are also comparing video learning with seminars, not in becoming a "master" of a particular martial art or other complete defense "system" and in that case, book, video and correspondence learning is pretty much an equivalently effective learning method. It is even more so if someone has had actual proper and effective in person instruction. Someone who already has fairly extensive training can usually take a video of a certain new technique or concept, study it, try it out, train it and be able to effectively apply it. We also have the modern benefit of email, so you can always follow up with any questions you have as most instructors are pretty accessible and open to questions or they at the very least have a presence on one or another self-defense forum. Plus, if video learning/DVDs are worthless, why does almost every single prominent instructors offer instructional DVDs? Are they dishonest charlatans offering a completely worthless product? If so, then why would you want to receive actual in person training from them?
I think a lot also depends on the individual. Some folks have a lot of natural ability and are very quick learners who can visually watch something once or even just read about it and understand it and even apply it while others need to study and train hard, be corrected constantly and ask question after question to even marginally understand and effectively apply it. And what about the most important skills? The first priority of true self-defense is to avoid the situation altogether. The most effective way not to get shot, stabbed or beat up is to not get into a violent confrontation in the first place, so avoidance skills such as situational awareness, de-escalation and escape strategies are the most important skills we need to study, understand and be able to implement and you do not need to have live, in person training to learn those skills. We have tremendous access to information available to us that I only dreamed of when I started training back in the 80's and to not take advantage of it because of some distorted idea that learning and understanding can only come directly from in person training rather than books, video or correspondence is nonsensical and severely limits opportunities of learning.