Theoretical physics has always studied theories that don't describe reality. It deepens our understanding of the theories that do describe reality. Eg., if you

Theoretical physics has always studied theories that don't describe reality. It deepens our understanding of the theories that do describe reality. Eg., if you change one axiom of a reality-describing-theory and certain naturally occurring phenomena disappears, then you can say that that axioms causes that that phenomena to occur. Also, this is not my field, but thousands of physics papers have been written on the AdS geometry (particularly the AdS-CFT duality). This line of thinking has brought a lot of clarity to string theory and to black hole physics.