Hi,
this is exactly what I need on my checkout too. There has to be a checkbox with the question if the user wants to subscribe the Newsletter or not. If checked it means "yes" if not checked it means "no". But the management has to be automatically, if not it's useless.
Who has the time and is willing to manually fiddle the subscribers day by day into the userlist.
Because all professional shops that I know have this function, I expect it as a standard feature for a shop. So would you implement this function for your users, please? I'm not a developer but I bet that this is just a few lines of code and a half day of work.