Since some motion occurs when electrons hit the protein, the possibility of recording movies and having better cameras allowed for higher resolution (basically you can see more details of the protein shape). With these new features, there was an explosion of new protein structures and the so-called resolution revolution with cryo-EM started. In fact, the 2017 Nobel prize in chemistry was awarded in honor of three of the main contributors to the development of cryo-EM \cite{Cressey2017}