The Cupcake Kart is the most popular kart in Kart Kingdom. It has been here since the beta days. It is mostly popular with new users. Even boys in Kart Kingdom wear this kart. You will find many people wearing this. The most common cupcake kart is the pink one. That's because The Pink Cupcake Kart is a starter kart for new users.
There was also an unused purple cupcake kart that was used only in the beta game trailer. Yumms567 discovered the .png file of it in the game files.