Some of them are good, just like some books are good, some movies are good, some games are good, etc.
There are certain shows that you could only exist as an animated cartoon, and others that could only exist as a live-action show. Specifically, animation tends to be just as expensive whether you're drawing boring realistic-looking people and places, or whether you're drawing unrealistic sci-fi or magic. If the show you want to make has lots of unrealistic stuff, it's probably a better idea to animate the whole thing, instead of just the special effects.
The reason people watch more Anime (Japanese animation) than cartoons (western animation) is because in the Western world, cartoons are generally considered to be just for kids. In Japan, animated shows can focus on more mature themes and plots, and there's a target audience that will watch those shows, too.