Isn't it? It somewhat-works in the browser but you don't get proper noise cancellation there nor quite some other features. Their native client is using an ancient version of Electron that, at least on Linux, leaves a lot to be desired. No audio-share, no proper Wayland support, no High-dpi.
There are quite a few amateur GitHub projects with patches and repacks to show how things should be done.
If a client is only good on Windows, then it is not that good. Remember Skype?