Any macro that is repeatable, like rapidfire or antirecoil, is considered cheating according to the EULA of pretty much any game. One-shot macros for the most part are still considered cheating, but some games allow them, such as World of Warcraft. Go to the Fortnite forums and you'll find posts about macros.
If you want to wear the risk, go ahead and use them. I personally don't have an issue with RF or AR (there's no need for either in Fortnite), as there's an accessibility justification for macroability, but I am aware that using them is in breach of the game's EULA.
My point is, don't be surprised if Epic lays down the banhammer for AA abuse because it is easy to detect in observe mode or a game recording. This is noteworthy because any player can view any other player in their recording.
It's also a breach of Twitch's terms of service to use macros in a multiplayer game, so it's not a smart idea to use them while streaming. I assume YouTube, Facebook and Mixer have similar policies.