An original cel may be in your future. You have fond memories of your childhood. You want to decorate your child's room in a special way. You are an artist or animator yourself. There are a lot of Disney, Warner etc.
Animation can nicely round out collections that involve golf, dogs, cats, hobbies, etc.
Beatles collectors may also enjoy collecting Yellow Sub art. Relative to other forms of original art to collect, animation can be a relatively inexpensive way of owning original art done by a famous individual or studio. A particular character reminds you of yourself or someone you know. There is a theme to your collection. For example, you collect all items dealing with the Disney villains.