@Deleted : Yes, that is still required. There are multiple reasons, one of those being that many of these environments are setup for app compatibility that still do require talking over a domain. Another large factor is that it's currently difficult to remote into an Azure AD Joined machine, since the connecting device must also be Azure AD Joined.
We are, however, tracking this work for the future to make it easier to deploy more lightweight Windows Virtual Desktop environments when you don't need full domain dependency.
