It's not a bad idea, but IMO it's a bad execution.
They're effectively running a business based on extorting everyone building anything for the web (everyone from big businesses to small hobbyists trying to make something new) by flat-out replacing the most common form of monetization (ads) with their own monetization and saying, "Hey developers, I know you worked hard on that website, so if you want that money (or, at least, a cut of it we feel is fair), sign up for our platform instead".