I get a bit worried when I read some of the posts frm CC on this forum.
I have a PPL, several hundred hours and over 20 hours in seriously run jet sim sessions, including simmed engine fires etc.
Also, I have flown regularly ince 1976, logging thousands of hours as pax and seeing a few "unusual " occurences.
In the back of a airliner, unless the wing was ablaze to an extent where it was about to fall off, I would find it very difficult to judge whether an evacuation was required - I simply do not have the level of training, systems understanding or experience.
With the very greatest of respect to CC, whom I respect for their knowledge of cabin procedures and generally very professional approach, I doubt that they would be in a better position than I.
So it seems, from the perspective of this regular SLF (and thus some part contributor to airline coffers), that the command authority should reside in the flightdeck with the people who are trained on the systems and have the experience to make the right decisions.
This is in no way meant to demean CC, who have an important part to play in the team, especially in feedng information to flightdeck, but it seems to me that as a rule of thumb that the captain should make the calls about evacuations.