Thank you for your message.
Yes, currently Viewer for Mac/Linux is available in Beta version only which has limited functionality. You can find the full list of currently supported features in the very first message on this page
Please note that the current screen capture mode does not consume additional traffic, however, more features that are already available in Viewer for Windows, including the multimonitor support, will be added in future updates of Viewer for Mac/Linux as well. Sorry for keeping you waiting.
Hope that helps.