Xnet is used for all sorts of purposes...it allows multiple machines to connect to one central one or "server". These machines can run a full copy of xlobby and operate all on their own (called fat clients), or they can run a simple executable and all commands/databases run on the server (called thin clients). Thin clients have their own screens to help "beutify" your control experience.
If I want to control what I see on tv remotly can I use xnet part of xLobby
You can surely control your xlobby machine this way. The only issue is speed. It usually takes a 1/2 second for commands that are sent from the thin client to be recognized by the server. If this is not an issue, then it is a very good way to control your system. Otherwise, get yourself a USB-UIRT and setup your remote, or a touchscreen and use a dual display option.
Oh and welcome to xlobby. The experience is sure enjoyable and rewarding when you get things going.