I use adblock on almost every website because some ads are still as annoying as they were in 1998. I don't like annoying moving things on websites or those stupid new autoplay videos so common on news websites. I block them all.
I use it on youtube because it's pointless watching ads about something I don't want/would never buy or watch short movie trailers (I cannot dodge them on my phone). I don't watch movies, I don't spend money on creams, deodorants and the stuff those ads try to sell and I never click on ads because the few times I did, they were scams like for example, mobile subscriptions (Hey, want to win a free iPod, accept this offer for free. Fineprint: subscription service, we will send you a handful of SMS a day about something you don't care or that we acknowledge is complete bullshit, at 15 times the cost of a regular SMS and YOU have to pay for each you receive). Nothing is free on the internet and anything served by ads is misleading most of the time or requires a purchase of some sort.
Also, I get that some people want/need to make money on their yt content but they have to carefully choose what to do, some go with all the options making the channel and videos beyond stupidly unusable, for example all the options from "InVideo programming" are useless bullshit and on mobile, the video/playlist suggestion eats up a huge chunk of the screen and the watermark overlay is pointless and not needed, accidental click on any of those items results in the video stopping and youtube sending you wherever and sometimes you cannot easily go back to the video you originally wanted to watch. There is no way of closing the suggestion or disabling the logo overlay (afaik).
Some choose to show a small leading ad video AND the in-video ads that show up while you're watching the content. That's a turnoff from the content for me and makes me want to stab someone.
Adblock comes to the rescue because it lets me watch and concentrate on the content. By default I keep annotations off on youtube so it shows no distractions (Like for example when they annotate the whole video in big fonts with "please like, watch this other video, or this other one, don't forget to like, and also sub. Please sub, it only takes one second").
And since I don't like that money/ad ridden youtube experience, I don't force any of my viewers to go trough that. I didn't monetize my channel and I don't allow youtube to show ads on any part of my videos. I only use music I have the rights to so nobody can complain about the media in my videos and try to make money based on claimed content.