For an example, I have this explode button GUI, and you don’t use it unless you’re on the other team. But in order to go to the other team, you have to die. So, if I just asked what team they’re on to keep the GUI there, would that make their client run faster to make less lag?
Disabled/non-visible guis rarely ever have an issue with lag, but if you want just that little tiny bit extra performance, or if the gui has any code within it, you could do that. Additionally, doing that will make it so cheaters cannot view the gui on the incorrect team. Though, it would be better for organizational purposes too.
TL;DR: If anything, its a better safeguard than a resource saver.