Because softwares are not the only one to use cycles. For example, in the GB, some memory space is only adressable during a few cycles, and so you have to opti

Because softwares are not the only one to use cycles. For example, in the GB, some memory space is only adressable during a few cycles, and so you have to optimize your code when you wish to update the video ram. If you miss the window, too bad.