I monetize simply because it makes me look and feel more official. If someone can't watch a 5 second, skippable ad, or a 15 second, non-skippable ad, why are they even watching my content anyways? You can only get an ad once every seven minutes (per. Tim Schmoyer of Video Creators) anyways so it's like if you're too anxious to get an ad over with, how can I expect you to fully indulge in my content and pull out every message possible from what I produce? If you can't watch an ad, you most likely can't watch a video. Pro monetization because I just think people think like "oh s**t, damn he's mad official he has ads on his videos, YouTube must like him" and it makes people take your more seriously. It's like if you workout in a shirt in the gym or a brand shirt in the gym. Regardless of how big the brand is, it's still a brand and people are going to look at you differently and probably think you're more serious about working out than others.
But, then again, this is only my opinion.