The terminal window is a secure replacement for Telnet connections. It offers a command-line interface to the remote host computer. Note that the most important function of the terminal window is to allow you to operate the remote host computer. Therefore the terminal window does not capture some common keyboard shortcuts (such as Ctrl+C for copy), but passes them instead to the remote host computer, where they can be used to control remote program execution.
Apart from the text display itself, a lot of connection information is visible in title and status bars of the terminal window.