Are macros allowed?

Can fortnite detect macros?

Fortnite uses a 3rd party software called EasyAntiCheat to prevent players from cheating in fortnite.  The makers of that software do not say if it detects macros or not.  But the software does block macro type of software such as autohotkey from working supposedly. Hardware type of macroing is not detectable, so if macros are required to play then find keyboards and mice that provide macroing onboard with out the use of software.

Should you use macros?

No, according to rules from Fortnite World Cup events, they specifically write in there rules the following:

"7.2.1    Each player is expected to play to the best of her or his ability at all times during any match.  Any form of unfair play is prohibited by these Rules, and may result in disciplinary action. Examples of unfair play include the following:

Using macro keys or similar methods to automate in-game actions." - source