In Japan, they have some serious protocol about greeting and showing respect toward your elder or your boss. The action of Miho here seems really disrespectful toward her mother since she is just there to get the money
That's like the most stereotypical phrase of disrespect you can say. Even in the west to just take a gift given to you and leave without even a proper thank you is considered pretty rude.
Here's your otoshidama.All right, kids.Short sleeves even in winterCheers.Otoshidama