Yeah, Kotaku isn't well-known for being the most reliable source. They have a couple writers known for being more reliable, but the website as a whole is usually less credible. The way I see it, YouTube counts as free advertising. You have someone reacting in real-time to your game. If they love it, their viewership will probably like it too. Will 100% of that viewership buy that game? No. Some of them might get enough enjoyment out of watching the YouTuber play the game. Some might be young children or people who don't have jobs - i.e. people who can't afford to buy the game. Some of them might not have the console that the game was released for, and they don't want to go out to buy a new console just to play one game. However, say the game gets ported to a console they do have, or say the person gets a job and can afford to buy games. They might decide to buy that game despite already seeing a playthrough, or they might decide to buy another game from that same developer. Is it guaranteed to make more people buy games from you? No. Is it guaranteed to make more people not buy games from you? Also no.