You cannot make a convention from just one example.
Ctrl-X signals are for long running shell applications. There are not many of them out there. Usually a long running application either has a GUI or is a commodity.
In pre-commodity times you could have used Ctrl-X signals as easy hot keys.
The only app I know which uses Ctrl-X signals other than Ctrl-C is Sahimi. It uses Ctrl-D to reset the console, Ctrl-E to empty its buffer and Ctrl-F to save the buffer to a file. Just like I said before, easy to use hot keys.