Is GitHub Copilot a blessing, or a curse?

GitHub Copilot is a new service from GitHub and OpenAI, described as "Your AI pair programmer". It is a plugin to Visual Studio Code which auto-generates code for you based on the contents of the current file, and your current cursor location. It really feels quite magical to use. For example, here I've typed the name and docstring of a function which should "Write text to file fname": The grey body of the function has been entirely written for me by Copilot! I just hit Tab on my keyboard, and the suggestion gets accepted and inserted into my code. This is certainly not the first "AI powered" program synthesis tool.