The Chinese noted the American activity:
U.S. Air Force B-52 bombers have carried out training in the vicinity of the South China Sea and the southern Japanese island of Okinawa, the Air Force said on Friday, in what a Chinese newspaper linked to China's drills near Taiwan.
I don't know if the Chinese fleet is taking part in those drills. But if they are, the American bomber exercises would have a more realistic training opportunity with a lot of Chinese warships to practice on.
And if Chinese ships aren't involved, exercising with Chinese aircraft in the air is a good defensive exercise for protecting the bombers at their launch points.
The B-52H has anti-ship capabilities.