Yes the purpose of the 3R Regenerator is to simplify the connections in a design. Normally you would need the original bit sequence and generated electrical signal along with the output transmitted signal to generate a realistic eye diagram. This component removes the need to make multiple forks and connections from the input. However, sometimes it can fail for very noisy systems or in some other cases where the global bit rate does not match the received bit rate. In these cases I generally use the input signals for the Eye Diagram Visualizer.
Regards