I curently don't see any aplication but i think there could be many !
I think there just miss something : /keybind <add/delete> ...
Exept that, i support
This should probably be clientside. It would let people bind common commands like /me, /home and world edit commands. Since it's clientside, it would be easy to let players bind things globally, and bring them from server to server.
I think people are misunderstanding the suggestion.
What it seems like this suggestion is suggesting is a way to bind commands to a specific key, keys which are set in an options menu, so the command can be executed with the key.
Player sets Keybind button 1 to NUMPAD1.
Mapmaker uses a command to apply [/time set day] to Keybind button 1.
Player presses NUMPAD1, and the command is executed.
That being said, I think it's a pretty neat feature, I don't know what all I'd use it for.