I still have a US bank account.
I think it's a good idea to keep a bank account in the US. You can use it to pay off American bills by direct debit, and you can also have American payments (tax refunds, income from investments, and when you are older, income from Social Security, pension and/or IRA) deposited directly into the US account.
Just remember that if you earn interest on the account you will have to pay US taxes for it.