1. Because we can press more weight using the press 2.0 than using a stretch reflex from the top. I have done and coached both extensively. The Press 2.0, once learned, is stronger. So: same ROM, same muscle mass, but more weight = better primary movement.
2. Because we can deadlift a lot more than we can RDL, we use the quads in a DL more than an RDL, and as you said, the ROM is greater. More muscle mass, more ROM, more weight = better primary movement.