Macaroon is a complex addon, with many features. It can use a larger amount of memory compared to other similar addons. However, one thing to understand is that memory usage in an addon has no direct impact on game performance. What impacts game performance is CPU usage.
The WoW client itself uses magnitudes more memory than the most memory intensive addons. If your computer can handle running WoW well, added memory usage by addons will not affect its performance. If your computer struggles to run WoW even at minimum settings, then addons are merely a straw on the proverbial camel's back.
CPU usage is another story. Addons do use CPU time, and the more they do, the more time they use. Macaroon, because of its nature, tends to use more CPU time than other addons of a similar nature. However, I am very, very focused on insuring CPU usage is within reason. If you ever experience an FPS drop and deem it to be related to Macaroon, please give me information on the FPS drop so that I may improve Macaroon!
So remember, in the majority of cases, especially if your computer already runs WoW well (set at average or above average settings) without addons, and you experience FPS issues, your addons are using more CPU time than your computer can keep a decent frame rate at. It is not a memory issue