Even without actual animation, this stuff has some key cartoon elements:
Really distinct and funny voices. Plus the acting and inherent comedic timing is great.
Great cartoon actors have to have that clear delivery that not only sounds natural, but focuses on the jokes. They know just where to pause before an accent and what to stress.Much full animation doesn't use strong vocal talent, but makes up for it with movement. If you don't have much movement you can sure benefit from funny, distinct voice actors.
Add funny and distinct character designs, and you have instant believable characters-even when they don't actually move.
Of course, I love it when you get all this and great full animation, like in 40s Warner Bros. cartoons, but it's rare to have all the elements that make good cartoons in one film or even one studio.
movie clip:
