Technically diplomatic ties haven't altered between Russia and the US directly. I'm sure there has been some drawdown of staff and maybe Russia has expelled some of the US diplomats they believed were spies.

Until direct confrontation begins being a serious outcome having an embassy on both ends gives a way to talk and avoid this. Also gives US citizens in Russia a way to get out should things start to sour.

Things like this aren't new. I'd fully expect someone to change the street outside the Russian embassy here to Ukraine Ave. or something in the near future.