Everything the server needs is inside the installer. No runtime to install first, no codec packs to hunt down, nothing downloaded during setup.
The runtime and a full media pipeline ship inside. Install it and open the page.
Every common container and codec is compiled in, so odd files play instead of failing.
Installs as a Windows service and starts with the machine. Or run it in a window when you feel like it.
Nothing is uploaded anywhere. The only thing that leaves your network is a heartbeat, and only if you connect it to an account.
The whole thing takes about a minute.