The decision applies to hobby users, but does not apply to commercial drone users who have to follow a separate set of standards which includes passing a test to get a license in order to fly.
“We are carefully reviewing the U.S. Court of Appeals decision as it relates to drone registrations,” according to a prepared statement from the FAA. “The FAA put registration and operational regulations in place to ensure that drones are operated in a way that is safe and does not pose security and privacy threats. We are in the process of considering our options and response to the decision.”
The court's full opinion is here.