The problem is that many chess videos are 10 minutes plus meaning they get a long pre roll ad and an ad in the middle interrupting. Sure, the viewers might not mind, but some might. And I know from the analytics there have been click through on longer ads. It's also about controlling the presentation of my content.
I think for growth and user experience staying unmonetized is a good option. The $13 a month is really not worth it in my opinion.
RE: Why I'm Demonetizing My Youtube Channel