The original challenge [0] was submitted as a "code-golf" challenge, which means that the solution needed to solve the problem in the fewest bytes of source cod

The original challenge [0] was submitted as a "code-golf" challenge, which means that the solution needed to solve the problem in the fewest bytes of source code. There are a lot of tricks to minimize the character count, and replacing a();b() with b(a()) is one of them. [0]: https://codegolf.stackexchange.com/q/196917/38454 https://codegolf.stackexchange.com/q/196917/38454