Wonder Woman Meets Baroness Von Gunther - S1-E2
Revealing mistake: After Wonder Woman saves Tommy from the falling ladder, when she uses her golden lasso to descend with Tommy (just a doll) we see her lasso (actually a thin rope) and its shadowy reflection on the windows, but we can also see the glistening of the stunt woman's safety cable as well.
Answer: The transformation twirling was invented for the 1970s TV series only, to explain her quick change from Diana Prince to Wonder Woman. However, it would have been nice to do a little spin homage in the movie.