Managed Apple ID's - 'Allow sign-in on managed devices only?'

I have generally not found this setting very useful as you still can’t limit what the domain is of an Apple Account being used to prevent personal Apple Accounts on Managed/Supervised devices.

Until Apple lets us limit the domains of Apple Accounts that can be used on Supervised devices, Apple Accounts really have no path forward in my mind.

I have been thinking about this as well.