Most of my money is way to big to fit into my bag!
you don't have the right size of mango to pay for these tickets.
Since mangoes are a fruit, they have the possibility of rotting after a certain amount of time. They can also break easily if dropped.
Mangoes can be different sizes, each being worth a different amount. Some can be very large, making it hard to transport. They are round and take up a lot of space, so they may not be considered the most efficient size/form of money.
The money cannot be cut in half or split up to be worth less. Different sizes are worth different amounts of money.