Scotland gets the pound anyway - Westminster can't stop them from having that. Westminster won't guarantee Scottish currency which would be normal, as why would a government guarantee another country's money?
"Ok you can do something that you were going to do anyway because we can't prevent you from doing it, if we get to keep Trident there lol" isn't really going to make a convincing deal.
Scotland gets the pound anyway - Westminster can't stop them from having that. Westminster won't guarantee Scottish currency which would be normal, as why would a government guarantee another country's money?
"Ok you can do something that you were going to do anyway because we can't prevent you from doing it, if we get to keep Trident there lol" isn't really going to make a convincing deal.