withDefaults setting array default values is different from props interface

[sschneider-ihre-pvs]

https://vuejs.org/api/sfc-script-setup.html#default-props-values-when-using-type-declaration

Why does the withDefaults need a function for setting defaults for arrays and not just an array?
My expectations would have been:

export interface Props {
  msg?: string
  labels?: string[]
}

const props = withDefaults(defineProps<Props>(), {
  msg: 'hello',
  labels: ['one', 'two']
})

But that is explicitly wrong, although the types of the interface seem to match

[Alfred-Skyblue]

Closure returns to prevent the same reference from being tampered with every time the component is called.