Why variable store is not needed for macOS guests

Hello

I have looked at Virtualization framework samples source code provided by Apple.

There is something strange: For a linux guest OS, i can see a variable store:

let variableStore = try VZEFIVariableStore(creatingVariableStoreAt: xxxx)
...
let bootloader = VZEFIBootLoader()
...
bootloader.variableStore = variableStore

It seems this variable store is linked with NVRAM.

For a macOS guest OS, there is no variable store. (The bootloader is created with VZMacOSBootLoader)

My question is why macOS guest doesn't need variable store ?

Thanks