Well, thats one of those , "thats the way it works in Graph" things :)
See:
https://office365itpros.com/2022/11/28/azure-ad-account-creation/
The New-MgUser cmdlet creates a new account. To run New-MgUser, we need a password profile. A password profile is a Microsoft Graph resource that contains a password and associated settings. It can be as simple as a password with no settings, but a password profile can also include settings like ForceChangePasswordNextSignIn to force a user account to change their password after they next sign into Azure AD.