you can get paid for putting ads on your video but not for watching them.
But keep in mind that unless your content is original, and is found to be very important, doing their partnership crap which puts additional ads on your videos, will drive away most of your viewers, and lead to negative votes. (many people will do this including me, put ads on your video and it will be much more likely to get a bad rating)
most pay sites are like this, users are exploited for low pay in order for the main site to engage in malicious activity.
there are some sites that will pay you to do surveys and watch some ads, but it is generally not worth your time since the amount of work you put in to how much money you get out of it, will add up to about 4-5 cents an hour.
The issue is that it works for some people. for example there are multiple sites (wont link to them) but will pay users to enter in captcha coded (generally $1 per 1000 captcha codes)
the sad thing is that there are actually people willing to work for those sites and spend hours typing captcha codes. (the end result of that is you get spam bots on sites with captcha (which is why captcha is not very effective and some sites will resort to the worst kind (eg the ones that are barely recognizable even for a human) (if you own a website, the only way around that is to resort to cognitive captchas, eg asking a user to correct the misspelled word in the message below, or some random trivia that is easy to solve with a quick google search. The bots cant answer them, and while they take more work, they don't have the problems with the user entering the wrong capture and being sent back to try again, only it wants you to re do almost the entire registration
Also wanted to add why you cant get paid to watch ads. The goal of an ad is to appeal to a target demographic in order to convince them to buy a product. If a service pays you to watch ads or if an ad pays you to watch it then the ad will not be any more likely to reach it's goal.
For example suppose there was a company that created an ad for their produce, lets pretend it is stool softener for rats. Now lets suppose you do not own a rat, how likely would you be to purchase the product after watching the ad? Now lets suppose the company was willing to pay you to watch the ad, how likely would you be to watch the ad and how likely would you be to purchase the product?
paying someone to watch an ad does not increase the likely hood that they will purchase a product.
The sites that engage in that practice generally get shutdown, for example, you can hire cashlagoon to significantly increase your ad revenue. what they will do is pay users $0.001 cents per ad click, the users on the site click on a link which takes them to your site and they are told to click on the ads.
When the ad companies find about it, they often drop the site as a customer or worst, they seek legal action for breach of terms of service.