I don't know about the rest of you, but I was recalibrated on this over the weekend when a couple of TV reporters were at JPL and got to touch and handle a full scale model (perhaps backup hardware). I envisioned this thing a couple of dozen cm tall, very toy like. Instead it is something like a meter and a half tall. The rotors span well over a meter. And at design speed are turning over 2000 rpm. Very advanced materials in the blades to deal with centrifugal effects.
The arguments about whether it is worth spending any time on this are complex without even bringing funding politics into it. Even assuming the primary mission is to find life (or ascertain whether life does or ever has existed) the helicopter might be important. If the proof of this does not happen to be along the rovers planned route the mission will fail. Mars orbiters can only provide some level of guidance on the path to follow. The mobile scouting capability provided by the helicopter might be important on this mission, and would certainly be important for a follow on mission if the question is not answered by the current rover. Thus there is potential value now, and real value in proving the technology for a future mission. The chance that this will not be answered soon is high given that all landers since Viking have had finding life some part of their purpose. Each has found tantalizing evidence that might be indicative of life, but none has been conclusive. Those launching each of these missions felt they were gathering the data that might answer the questions, but Mars proved mysterious.