Other compelling reasons why you might want to create 64-bit applications include:
You need to perform a lot of computation on 64-bit integer quantities that use the wider data paths of a 64-bit processor to gain performance.
Several system interfaces have been enhanced, or limitations removed, because the underlying data types that underpin those interfaces have become larger.
You want to obtain the performance benefits of the 64-bit instruction set, such as improved calling conventions and full use of the register set.