On one of the slides, a picture shows the energy levels for increasing spin I. For half-integer spin, the energy levels remain degenerate. For integer spin, they split for \eta going to 1 (no axial symmetry). This means that the classical picture (all energy values are allowed) will be reached when considering high integer spin (I –> \inf, I integer) in situations away from axial symmetry (\eta –> 1).