I uploaded a few videos to YouTube, and just found a checkbox titled "Allow advertisements to be displayed alongside my videos" on https://www.youtube.com/advanced_settings when looking around.
At first, I thought that maybe that's for making money from your videos and was surprised it was checked (because I didn't (consciously) check it as I don't plan to make money from my videos). But then I saw that it says
Does not apply to videos that you monetize and videos that are claimed by a third-party.
in small, gray text below it.
So monetizing is something different, it seems. Is this correct?
If so: Why does YouTube give their users the option to choose whether there will be ads on their videos? If there are no ads on a video, YouTube can't make money from it.
If not: Why does it say the setting doesn't apply to monetization?
Am I or are my viewers given any disadvantage if I uncheck this box? Does it mean they will never see ads when watching my videos?