EXPAT FAQ
https://www.easyexpat.com/en/faq.htm
US citizens: Do I still need to fill a tax form if I become a British Citizen?
Filing a US return is not a choice for US citizens or Greencard holders, rather it is a requirement in accordance with the legislations regardless of where in the world they live, how long they live there for, or whether or not they obtain the passport of that country.
There are even rules for those individuals who give up their US nationality or Greencard which requires them to file a return after doing so (expatriation rules).
So, the answer is: there is no benefit to filing a US tax return, but you don't have a choice in the matter as long as you are still a US citizen as well.