As the title says, what are the risks, I assume people don’t host these servers for no reason. Is it just the ad revenue they get from the popups when trying to start the movie.
Could they be running exploits on here that would make it not safe at all to do so?
You can run adblockers and other privacy extensions in Safari. Unfortunately Firefox on iOS doesn’t support extensions, because it still uses Safari to display the pages (iOS is dumb that way).