The idea is to support Linux desktops like Ubuntu and Fedora. Currently, only the web client is available for Linux, but many features are not available.
I actually got the web based AVD to work at a usable frame rate. I had to enabled chrome/edge flags so that I could get a usable refresh rate that wasn't like viewing a slide show. The flags to enable were the enhanced-gpu-rasterisation and/or #enable-webgl-developer-extensions.
I built native client with feed discovery just like the windows app you are talking about. it will also with with all yours devices like audio, webcam etc. https://dev.to/rana_tigrina2002/i-built-the-linux-client-for-azure-virtual-desktop-that-microsoft-never-shipped-219p