AngelScript (or any embedded scripting solution) is often used as event handlers.
You would compile the scripts once, e.g. when loading the level data, and then the compiled script functions are called as the game engine detects that a specific event occurred (e.g. the user pressed a button). This way you allow script writer to decide what should happen when the button is pressed, for example, write a message to the console, or fire the player's gun, etc.
You do not want to recompile the script every time you need to call a script. If you're planning on allowing the user to change the script dynamically during the game's execution, then recompile only when the script has actually changed.