The reason for the change is to help the film crew identify if the tip of the serpent is in the shot, particularly in low light situations.
The transparent one was harder to see, even if it did accidentally make it into the shot, but once you knew it was there, it was impossible to ignore. With the green-glow tip, it should be immediately obvious if any part of it can be seen. No more “I-didn’t-see-it-at-the-time-but-now-we’re-in-editing-there-it-is” snafus.
Let us know what you think!