You cannot underestimate the power of any information in any form. I have heard people say that just one video on YouTube changed their lives. How effective a video will be determined by the content and the viewer's needs. If the right information a gambler needs is in the video it could be transformational. All content creators want to make money, but some are focused on giving out quality content that can be beneficial to viewers.
Ten therapy sessions won't change a compulsive gambler, not to talk of a single video. Changing problem gamblers doesn't happen that way, a lot of work goes into fixing the player's brain or emotions. Do you know that atimes conversations get countervailing for the player, such that they'll get aggressive on their therapist. Hence, it's not a day's job, or something a simple video made by a person who is not a therapist could impact on.
Your conclusion is based on your personal experience or research. Maybe you have experience with gambling addicts who struggled to overcome it. Maybe they went through different processes to overcome it. But this wouldn't dispute my observation that a single message can transform the life of someone suffering from a gambling disorder. You are right doesn't make my position wrong.