Video codecs are designed primarily for imagery coming from a camera. They don't cope with sharp edges like vector shapes especially well - edges get blurry and blocky. Videos are also not scalable; if you stretch them for a bigger screen or zoom in, they get pixelated. You can encode with more sharpness or higher resolution, but that makes your files bigger.

Little uses a vector format, so the results are sharp whatever the scale, with the same file size. However, each additional picture element may cost more in comparison.

Some animations will be best in one, some in the other.