A common example of this might be player UI colour preference. You could store this value on each UI controller that needs to use it and thus when this value changes you need to go out and update all references to it. Alternatively, you could use a singleton to hold the value, but this then creates a large and wide reaching dependency chain that will make unit testing difficult if not impossible. Finally, you could create a system to look this value up such as to read it from app settings or similar, this however incurs processing overhead for everything that uses it and thus does not scale well at all.