Why it worked
The video uses a common pet owner trope of a pet "talking" to express affection and a desire for companionship. The humor comes from the dog's logical (though flawed) reasoning about how to keep her owner home, and the relatable "daddy still has money" punchline.
Summary
A dog named Dodo pretends to not be hungry so her owner can stay home with her. Dodo explains that if she eats less, her mom won't have to work as hard to buy her food. She then reveals that her dad still has money, implying he can provide for them, and expresses her love for him.