The name Windows App is so confusing. As an admin, when I first heard about it, I thought it's another iteration of admin tools for Windows.
When I first mentioned it to our developers, they thought it's the name for apps developed using the Windows App SDK (which made me wonder for a moment why an SDK is needed for accessing remote desktops and apps). When I explained that it's for remote access, some of them assumed it's specifically for apps developed with the Windows App SDK.
I can see end users being even more confused, with some thinking it refers to apps from the Microsoft Store (formerly known as the Windows Store). Which brings up another point; it's going to make it harder to find in the Microsoft Store, Apple App Store, Google Play store, and on-device searches for the app.
I also find it a bit ironic that the name is being changed to Windows App as more Linux distributions are enabling Remote Desktop access to their desktops.