IMHO Windows App is not yet a full replacement for the Remote Desktop Client or the AVD Preview Client. Why? Because of essential shortcomings.
No integration with local start menu; A lot of my customers use AVD to publish RemoteApp applications, moving away from VPN's. Providing a seamless experience from Start Menu is added value for the user. As long as this functionality is lacking in Windows App, customers won't shift to Windows App in RemoteApp usecases.
Private Link not supported; Usecases with specific requirements to regulate connectivity to AVD session hosts. With new technology on connectivity, you still need the Remote Desktop client.
ADFS not supported; Many organizations are still trying to move away from complex ADFS authentication infrastructure to Password Hash Sync or other EntraID authentication option. But many organizations have specific authentication requirements to stick with ADFS or similar form of federated authentication. With Windows App that fits seamlessly in Windows 11 fresh user experience, cannot support ADFS?
Windows App released to early? Or are above features under construction for Windows App?