Record currency in MySQL

The currency is in the database MySQL Commonly used Decimal and Numric Type said , These two types are MySQL Implement the same type .

Why use Decimal and Numric type , Rather than using float and double Type? ？
reason ：DECIMAL and NUMERIC Values are stored as strings , Not as binary floating-point numbers , In order to save the decimal precision of those values . and float and double It's stored in binary , There is a certain error , Data type not suitable for amount storage .