Bab 72: Chapter 71 Whale Specific Card

The friendly aid feature achieved three different goals.

First, weaker players will be able to clear some levels that they can't clear themselves with the aid of stronger accounts. This presents itself as a stronger player carrying the weaker one, and in turn the weaker player will feel as though they weren't playing alone, making the game feel more social, and increasing the player retention of weaker players. 

Second, stronger players with stronger cards achieve an advertising effect, showing everyone on their friends list how strong the card is, incentivising other players to spend money in game as well.

Third, the non-playing players will naturally flock to the stronger whales, flooding them with friend requests. This makes the stronger players feel a great sense of satisfaction, further encouraging them to spend more money.